Aruba Layer 3—IP Routing Configuration Guide

HPE FlexFabric 5940 & 5930 Switch Series

Layer 3—IP Services Configuration Guide

P

art number: 5200-4874d

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version: Release 2609 and later

Document version: 6W103-20200310

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Contents

Configuring ARP ·············································································· 1

Overview ·································································································································· 1

ARP message format ··········································································································· 1

ARP operating mechanism ···································································································· 1

ARP table ·························································································································· 2

Configuring a static ARP entry ······································································································ 3

Configuring a multiport ARP entry ·································································································· 4

Setting the maximum number of dynamic ARP entries for a device ······················································· 5

Setting the maximum number of dynamic ARP entries for an interface ·················································· 5

Setting the aging timer for dynamic ARP entries ··············································································· 6

Enabling dynamic ARP entry check ······························································································· 6

Synchronizing ARP entries ··········································································································· 6

Configuring a customer-side port ··································································································· 7

Enabling ARP logging ················································································································· 7

Displaying and maintaining ARP ··································································································· 8

Configuration examples ··············································································································· 8

Long static ARP entry configuration example ············································································· 8

Short static ARP entry configuration example ············································································ 9

Multiport ARP entry configuration example ·············································································· 10

Configuring gratuitous ARP ······························································ 13

Overview ································································································································ 13

Gratuitous ARP packet learning ···························································································· 13

Periodic sending of gratuitous ARP packets ············································································ 13

Configuration procedure ············································································································ 14

Enabling IP conflict notification ···································································································· 14

Configuring gratuitous ARP packet retransmission for the device MAC address change ·························· 15

Configuring proxy ARP ···································································· 16

Enabling common proxy ARP ····································································································· 16

Enabling local proxy ARP ·········································································································· 16

Displaying proxy ARP ··············································································································· 16

Common proxy ARP configuration example ··················································································· 17

Network requirements ········································································································ 17

Configuration procedure ····································································································· 17

Verifying the configuration ··································································································· 18

Configuring ARP snooping ······························································· 19

Configuration procedure ············································································································ 19

Displaying and maintaining ARP snooping ···················································································· 19

Configuring ARP fast-reply ······························································· 20

Overview ································································································································ 20

Configuration procedure ············································································································ 20

ARP fast-reply configuration example ··························································································· 20

Network requirements ········································································································ 20

Configuration procedure ····································································································· 21

Configuring ARP direct route advertisement ········································· 22

Mechanism of ARP direct route advertisement ········································································· 22

Application in Layer 3 access networks ·················································································· 22

Configuration procedure ············································································································ 22

Configuring IP addressing ································································ 23

Overview ································································································································ 23

IP address classes ············································································································ 23

Special IP addresses ········································································································· 24

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Subnetting and masking ····································································································· 24

Assigning an IP address to an interface ························································································ 24

Configuration guidelines ····································································································· 25

Configuration procedure ····································································································· 25

Configuring IP unnumbered ········································································································ 26

Configuration guidelines ····································································································· 26

Configuration prerequisites ·································································································· 26

Configuration procedure ····································································································· 26

Displaying and maintaining IP addressing ····················································································· 26

IP address configuration example ································································································ 27

Network requirements ········································································································ 27

Configuration procedure ····································································································· 27

Verifying the configuration ··································································································· 27

DHCP overview ············································································· 29

DHCP network model ··············································································································· 29

DHCP address allocation ··········································································································· 29

Allocation mechanisms ······································································································· 29

IP address allocation process ······························································································ 30

IP address lease extension ·································································································· 30

DHCP message format ············································································································· 31

DHCP options ························································································································· 32

Common DHCP options ······································································································ 32

Custom DHCP options ······································································································· 32

Protocols and standards ············································································································ 34

Configuring the DHCP server ···························································· 35

Overview ································································································································ 35

DHCP address pool ··········································································································· 35

IP address allocation sequence ···························································································· 37

DHCP server configuration task list ······························································································ 37

Configuring an address pool on the DHCP server ··········································································· 38

Configuration task list ········································································································· 38

Creating a DHCP address pool ···························································································· 38

Specifying IP address ranges for a DHCP address pool ····························································· 38

Specifying gateways for DHCP clients ··················································································· 41

Specifying a domain name suffix for DHCP clients ···································································· 42

Specifying DNS servers for DHCP clients ··············································································· 42

Specifying WINS servers and NetBIOS node type for DHCP clients ············································· 42

Specifying BIMS server for DHCP clients ················································································ 43

Specifying the configuration file for DHCP client auto-configuration ·············································· 43

Specifying a server for DHCP clients ····················································································· 44

Configuring Option 184 parameters for DHCP clients ································································ 44

Customizing DHCP options ································································································· 45

Configuring the DHCP user class whitelist ·············································································· 47

Enabling DHCP ······················································································································· 47

Enabling the DHCP server on an interface ···················································································· 47

Applying an address pool on an interface ······················································································ 48

Configuring a DHCP policy for dynamic address assignment ····························································· 48

Configuring IP address conflict detection ······················································································· 49

Enabling handling of Option 82 ··································································································· 50

Configuring the DHCP server security features ··············································································· 50

Restrictions and guidelines ·································································································· 50

Configuring DHCP flood attack protection ··············································································· 50

Configuring DHCP starvation attack protection ········································································ 51

Configuring DHCP server compatibility ························································································· 51

Configuring the DHCP server to broadcast all responses ··························································· 51

Configure the DHCP server to ignore BOOTP requests ····························································· 52

Configuring the DHCP server to send BOOTP responses in RFC 1048 format ······························· 52

Setting the DSCP value for DHCP packets sent by the DHCP server ·················································· 53

Configuring DHCP binding auto backup ························································································ 53

Configuring address pool usage alarming ······················································································ 53

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Applying a DHCP address pool to a VPN instance ·········································································· 54

Enabling client offline detection on the DHCP server ······································································· 54

Enabling DHCP logging on the DHCP server ················································································· 55

Displaying and maintaining the DHCP server ················································································· 55

DHCP server configuration examples ··························································································· 56

Static IP address assignment configuration example ································································· 56

Dynamic IP address assignment configuration example ····························································· 57

DHCP user class configuration example ················································································· 59

DHCP user class whitelist configuration example ····································································· 61

Primary and secondary subnets configuration example ····························································· 62

DHCP option customization configuration example ··································································· 63

Troubleshooting DHCP server configuration ·················································································· 65

Symptom ························································································································· 65

Analysis ·························································································································· 65

Solution ··························································································································· 65

Configuring the DHCP relay agent ····················································· 66

Overview ································································································································ 66

Operation ························································································································ 66

DHCP relay agent support for Option 82 ················································································· 67

DHCP relay agent configuration task list ······················································································· 67

Enabling DHCP ······················································································································· 68

Enabling the DHCP relay agent on an interface ·············································································· 68

Specifying DHCP servers on a relay agent ···················································································· 69

Configuring the DHCP relay agent security features ········································································ 69

Enabling the DHCP relay agent to record relay entries ······························································ 69

Enabling periodic refresh of dynamic relay entries ···································································· 69

Configuring DHCP flood attack protection ··············································································· 70

Enabling DHCP starvation attack protection ············································································ 70

Configuring the DHCP relay agent to release an IP address ······························································ 71

Configuring Option 82 ··············································································································· 72

Setting the DSCP value for DHCP packets sent by the DHCP relay agent ············································ 72

Enabling DHCP server proxy on the DHCP relay agent ···································································· 73

Configuring a DHCP address pool on the DHCP relay agent ····························································· 73

Specifying the DHCP relay agent address to be inserted in DHCP requests ········································· 74

Enabling client offline detection on the DHCP relay agent ································································· 74

Configuring the DHCP smart relay feature ····················································································· 75

Specifying the DHCP server selecting algorithm ············································································· 76

Specifying the source IP address for DHCP requests······································································· 78

Discarding DHCP requests that are delivered from VXLAN tunnels ····················································· 78

About discarding DHCP requests that are delivered from VXLAN tunnels ······································ 78

Procedure ························································································································ 78

Configuring the DHCP relay agent to forward DHCP replies based on the MAC address table·················· 79

Displaying and maintaining the DHCP relay agent ·········································································· 80

DHCP relay agent configuration examples ···················································································· 80

DHCP relay agent configuration example ··············································································· 80

Option 82 configuration example ·························································································· 81

DHCP server selection configuration example ········································································· 82

Troubleshooting DHCP relay agent configuration ············································································ 83

Symptom ························································································································· 83

Analysis ·························································································································· 83

Solution ··························································································································· 83

Configuring the DHCP client ····························································· 84

Enabling the DHCP client on an interface ······················································································ 84

Configuring a DHCP client ID for an interface ················································································· 84

Enabling duplicated address detection ·························································································· 85

Setting the DSCP value for DHCP packets sent by the DHCP client ··················································· 85

Displaying and maintaining the DHCP client ·················································································· 85

DHCP client configuration example ······························································································ 86

Network requirements ········································································································ 86

Configuration procedure ····································································································· 86

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Verifying the configuration ··································································································· 87

Configuring DHCP snooping ····························································· 88

Overview ································································································································ 88

Application of trusted and untrusted ports ··············································································· 88

DHCP snooping support for Option 82 ··················································································· 89

DHCP snooping configuration task list ·························································································· 90

Configuring basic DHCP snooping ······························································································· 90

Configuring basic DHCP snooping features in a common network ··············································· 90

Configuring basic DHCP snooping features in a VXLAN network ················································· 91

Configuring Option 82 ··············································································································· 93

Configuring DHCP snooping entry auto backup ·············································································· 93

Enabling DHCP starvation attack protection ··················································································· 94

Enabling DHCP-REQUEST attack protection ················································································· 95

Setting the maximum number of DHCP snooping entries ·································································· 95

Configuring DHCP packet rate limit ······························································································ 96

Configuring a DHCP packet blocking port ······················································································ 96

Enabling DHCP snooping logging ································································································ 96

Disabling DHCP snooping on an interface ····················································································· 97

Displaying and maintaining DHCP snooping ·················································································· 97

DHCP snooping configuration examples ······················································································· 98

Global basic DHCP snooping configuration example ································································· 98

VLAN-specific DHCP snooping configuration example ······························································ 99

Option 82 configuration example ························································································ 100

Configuring the BOOTP client ························································· 102

BOOTP application················································································································· 102

Obtaining an IP address dynamically ·························································································· 102

Protocols and standards ·········································································································· 102

Configuring an interface to use BOOTP for IP address acquisition ···················································· 102

Displaying and maintaining BOOTP client ··················································································· 103

BOOTP client configuration example ·························································································· 103

Network requirements ······································································································ 103

Configuration procedure ··································································································· 103

Verifying the configuration ································································································· 103

Configuring DNS ·········································································· 104

Overview ······························································································································ 104

Static domain name resolution ··························································································· 104

Dynamic domain name resolution ······················································································· 104

DNS proxy ····················································································································· 105

DNS spoofing ················································································································· 106

DNS configuration task list ······································································································· 107

Configuring the IPv4 DNS client ································································································ 107

Configuring static domain name resolution ············································································ 107

Configuring dynamic domain name resolution ········································································ 108

Configuring the IPv6 DNS client ································································································ 109

Configuring static domain name resolution ············································································ 109

Configuring dynamic domain name resolution ········································································ 109

Configuring the DNS proxy ······································································································· 110

Configuring DNS spoofing ········································································································ 111

Specifying the source interface for DNS packets ··········································································· 111

Configuring the DNS trusted interface ························································································ 112

Setting the DSCP value for outgoing DNS packets ········································································ 112

Displaying and maintaining DNS ······························································································· 112

IPv4 DNS configuration examples ····························································································· 113

Static domain name resolution configuration example ····························································· 113

Dynamic domain name resolution configuration example ························································· 113

DNS proxy configuration example ······················································································· 116

IPv6 DNS configuration examples ····························································································· 117

Static domain name resolution configuration example ····························································· 117

Dynamic domain name resolution configuration example ························································· 118

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DNS proxy configuration example ······················································································· 120

Troubleshooting IPv4 DNS configuration ····················································································· 122

Failure to resolve IPv4 addresses ······················································································· 122

Troubleshooting IPv6 DNS configuration ····················································································· 122

Failure to resolve IPv6 addresses ······················································································· 122

Configuring DDNS ········································································ 123

Overview ······························································································································ 123

DDNS application ············································································································ 123

DDNS client configuration task list ····························································································· 124

Configuring a DDNS policy ······································································································· 124

Configuration prerequisites ································································································ 125

Configuration procedure ··································································································· 125

Applying the DDNS policy to an interface ···················································································· 126

Setting the DSCP value for outgoing DDNS packets ······································································ 126

Displaying DDNS ··················································································································· 127

DDNS configuration examples ·································································································· 127

DDNS configuration example with www.3322.org ··································································· 127

DDNS configuration example with PeanutHull server ······························································ 128

Configuring IP forwarding basic settings ············································ 130

FIB table ······························································································································ 130

Saving the IP forwarding entries to a file ····················································································· 130

Enabling split horizon forwarding ······························································································· 131

Displaying FIB table entries ······································································································ 131

Configuring load sharing ································································ 132

Configuring load sharing ·········································································································· 132

Enabling local-first load sharing ································································································· 132

Enabling symmetric load sharing ······························································································· 132

Displaying and maintaining load sharing ····················································································· 133

Load sharing configuration example ··························································································· 133

Network requirements ······································································································ 133

Configuration procedure ··································································································· 133

Verifying the configuration ································································································· 135

Configuring fast forwarding ····························································· 136

Overview ······························································································································ 136

Configuring the aging time for fast forwarding entries ····································································· 136

Configuring fast forwarding load sharing ····················································································· 136

Displaying and maintaining fast forwarding ·················································································· 136

Displaying the adjacency table ························································ 138

Configuring IRDP ········································································· 140

Overview ······························································································································ 140

IRDP operation ··············································································································· 140

Basic concepts ··············································································································· 140

Protocols and standards ··································································································· 141

Configuration procedure ·········································································································· 141

IRDP configuration example ····································································································· 142

Network requirements ······································································································ 142

Configuration procedure ··································································································· 142

Verifying the configuration ································································································· 143

Optimizing IP performance ····························································· 144

Enabling an interface to forward directed broadcasts destined for the directly connected network ··········· 144

Configuration procedure ··································································································· 144

Configuration example ······································································································ 144

Setting the interface MTU for IPv4 packets ·················································································· 145

Setting TCP MSS for an interface ······························································································ 145

Configuring TCP path MTU discovery ························································································· 146

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Enabling SYN Cookie ············································································································· 147

Setting the TCP buffer size ······································································································ 147

Setting TCP timers ················································································································· 147

Enabling sending ICMP error messages ····················································································· 148

Disabling forwarding ICMP fragments ························································································· 149

Configuring rate limit for ICMP error messages············································································· 150

Specifying the source address for ICMP packets ·········································································· 150

Enabling IPv4 local fragment reassembly ···················································································· 150

Displaying and maintaining IP performance optimization ································································ 151

Configuring UDP helper ································································· 152

Overview ······························································································································ 152

Configuration restrictions and guidelines ····················································································· 152

Configuring UDP helper to convert broadcast to unicast ································································· 152

Configuring UDP helper to convert broadcast to multicast ······························································· 153

Displaying and maintaining UDP helper ······················································································ 153

UDP helper configuration examples ··························································································· 154

Configuring UDP helper to convert broadcast to unicast ·························································· 154

Configuring UDP helper to convert broadcast to multicast ························································ 155

Configuring basic IPv6 settings ······················································· 157

Overview ······························································································································ 157

IPv6 features ·················································································································· 157

IPv6 addresses ··············································································································· 158

IPv6 ND protocol ············································································································· 160

IPv6 path MTU discovery ·································································································· 162

IPv6 transition technologies ······································································································ 163

Dual stack ······················································································································ 163

Tunneling ······················································································································ 163

6PE ······························································································································ 164

Protocols and standards ·········································································································· 164

IPv6 basics configuration task list ······························································································ 164

Assigning IPv6 addresses to interfaces ······················································································· 165

Configuring an IPv6 global unicast address ··········································································· 165

Configuring an IPv6 link-local address ················································································· 168

Configuring an IPv6 anycast address ··················································································· 169

Configuring IPv6 ND ··············································································································· 169

Configuring a static neighbor entry ······················································································ 169

Setting the maximum number of dynamic neighbor entries ······················································· 170

Setting the aging timer for ND entries in stale state ································································· 170

Minimizing link-local ND entries ·························································································· 170

Setting the hop limit ········································································································· 171

Configuring parameters for RA messages ············································································· 171

Setting the maximum number of attempts to send an NS message for DAD ································· 173

Configuring ND snooping ·································································································· 174

Enabling ND proxy ··········································································································· 175

Configuring path MTU discovery ······························································································· 177

Setting the interface MTU for IPv6 packets ··········································································· 177

Setting a static path MTU for an IPv6 address ······································································· 177

Setting the aging time for dynamic path MTUs ······································································· 178

Controlling sending ICMPv6 messages ······················································································· 178

Configuring the rate limit for ICMPv6 error messages ······························································ 178

Enabling replying to multicast echo requests ········································································· 179

Enabling sending ICMPv6 destination unreachable messages ·················································· 179

Enabling sending ICMPv6 time exceeded messages ······························································ 179

Enabling sending ICMPv6 redirect messages ········································································ 180

Specifying the source address for ICMPv6 packets ································································· 180

Enabling IPv6 local fragment reassembly ···················································································· 181

Enabling a device to discard IPv6 packets that contain extension headers ········································· 181

Displaying and maintaining IPv6 basics ······················································································ 181

IPv6 configuration examples ····································································································· 182

Basic IPv6 configuration example ······················································································· 182

vii

ND snooping configuration example ···················································································· 187

Troubleshooting IPv6 basics configuration ··················································································· 189

Symptom ······················································································································· 189

Solution ························································································································· 189

DHCPv6 overview ········································································ 190

DHCPv6 address/prefix assignment ··························································································· 190

Rapid assignment involving two messages ··········································································· 190

Assignment involving four messages ··················································································· 190

Address/prefix lease renewal ···································································································· 191

Stateless DHCPv6 ················································································································· 192

Protocols and standards ·········································································································· 192

Configuring the DHCPv6 server ······················································ 193

Overview ······························································································································ 193

IPv6 address assignment ·································································································· 193

IPv6 prefix assignment ····································································································· 193

Concepts ······················································································································· 194

DHCPv6 address pool ······································································································ 194

IPv6 address/prefix allocation sequence ··············································································· 195

Configuration task list·············································································································· 196

Configuring IPv6 prefix assignment ···························································································· 196

Configuration guidelines ··································································································· 196

Configuration procedure ··································································································· 197

Configuring IPv6 address assignment ························································································ 198

Configuration guidelines ··································································································· 198

Configuration procedure ··································································································· 198

Configuring network parameters assignment ··············································································· 199

Configuring network parameters in a DHCPv6 address pool ····················································· 199

Configuring network parameters in a DHCPv6 option group ····················································· 200

Configuring a DHCPv6 policy for IPv6 address and prefix assignment ··············································· 201

Configuring the DHCPv6 server on an interface ············································································ 202

Configuration guidelines ··································································································· 202

Configuration procedure ··································································································· 202

Setting the DSCP value for DHCPv6 packets sent by the DHCPv6 server ·········································· 203

Configuring DHCPv6 binding auto backup ··················································································· 203

Applying a DHCPv6 address pool to a VPN instance ····································································· 204

Enabling the DHCPv6 server to advertise IPv6 prefixes ·································································· 204

Enabling DHCPv6 logging on the DHCPv6 server ········································································· 204

Displaying and maintaining the DHCPv6 server ············································································ 205

DHCPv6 server configuration examples ······················································································ 206

Dynamic IPv6 prefix assignment configuration example ··························································· 206

Dynamic IPv6 address assignment configuration example ······················································· 208

Configuring the DHCPv6 relay agent ················································ 211

Overview ······························································································································ 211

DHCPv6 relay agent configuration task list ·················································································· 212

Enabling the DHCPv6 relay agent on an interface ········································································· 212

Specifying DHCPv6 servers on the relay agent ············································································ 213

Setting the DSCP value for DHCPv6 packets sent by the DHCPv6 relay agent ··································· 213

Specifying a padding mode for the Interface-ID option ··································································· 213

Enabling the DHCPv6 relay agent to support Option 79·································································· 214

Configuring a DHCPv6 address pool on the DHCPv6 relay agent ····················································· 214

Specifying a gateway address for DHCPv6 clients ········································································ 215

Enabling the DHCPv6 relay agent to record relay entries ································································ 215

Enabling IPv6 release notification ······························································································ 216

Enabling client offline detection ································································································· 216

Enabling the DHCPv6 relay agent to advertise IPv6 prefixes ··························································· 216

Specifying the source IPv6 address for relayed DHCPv6 requests ···················································· 217

Displaying and maintaining the DHCPv6 relay agent ····································································· 217

DHCPv6 relay agent configuration example ················································································· 218

Network requirements ······································································································ 218

viii

Configuration procedure ··································································································· 218

Verifying the configuration ································································································· 219

Configuring the DHCPv6 client ························································ 220

Overview ······························································································································ 220

DHCPv6 client configuration task list ·························································································· 220

Configuring IPv6 address acquisition ·························································································· 220

Configuring IPv6 prefix acquisition ····························································································· 221

Configuring IPv6 address and prefix acquisition ············································································ 221

Configuring stateless DHCPv6 ·································································································· 221

Configuring the DHCPv6 client DUID ························································································· 222

Setting the DSCP value for DHCPv6 packets sent by the DHCPv6 client ··········································· 222

Displaying and maintaining DHCPv6 client ·················································································· 222

DHCPv6 client configuration examples ······················································································· 223

IPv6 address acquisition configuration example ····································································· 223

IPv6 prefix acquisition configuration example ········································································ 224

IPv6 address and prefix acquisition configuration example ······················································· 226

Stateless DHCPv6 configuration example ············································································· 228

Configuring DHCPv6 snooping ························································ 230

Overview ······························································································································ 230

Application of trusted and untrusted ports ············································································· 230

Implementation of Option 18 and Option 37 ················································································· 231

Option 18 for DHCPv6 snooping ························································································· 231

DHCPv6 snooping support for Option 37 ·············································································· 232

DHCPv6 snooping configuration task list ····················································································· 232

Configuring basic DHCPv6 snooping ·························································································· 233

Configuring Option 18 and Option 37 ························································································· 233

Configuring DHCPv6 snooping entry auto backup ········································································· 234

Setting the maximum number of DHCPv6 snooping entries ····························································· 234

Configuring DHCPv6 packet rate limit ························································································· 235

Enabling DHCPv6-REQUEST check ·························································································· 235

Configuring a DHCPv6 packet blocking port ················································································ 236

Enabling DHCPv6 snooping logging ··························································································· 236

Displaying and maintaining DHCPv6 snooping ············································································· 236

DHCPv6 snooping configuration example ··················································································· 237

Network requirements ······································································································ 237

Configuration procedure ··································································································· 237

Verifying the configuration ································································································· 238

Configuring IPv6 fast forwarding ······················································ 239

Overview ······························································································································ 239

Configuring the aging time for IPv6 fast forwarding entries ······························································ 239

Configuring IPv6 fast forwarding load sharing ·············································································· 239

Displaying and maintaining IPv6 fast forwarding ··········································································· 240

Configuring tunneling ···································································· 241

Overview ······························································································································ 241

Configuring a tunnel interface ··································································································· 241

Adding TUNNEL to the PHY_UPDOWN log mnemonic for tunnel interfaces ······································· 243

Displaying and maintaining tunneling configuration ······································································· 243

Troubleshooting tunneling configuration ······················································································ 243

Symptom ······················································································································· 243

Analysis ························································································································ 243

Solution ························································································································· 244

IPv6 over IPv4 tunneling ································································ 245

Overview ······························································································································ 245

Implementation ··············································································································· 245

Tunnel modes ················································································································· 245

IPv6 over IPv4 tunneling configuration task list ············································································· 247

Configuring an IPv6 over IPv4 manual tunnel ··············································································· 247

ix

Restrictions and guidelines ································································································ 247

Procedure ······················································································································ 248

Configuration example ······································································································ 248

Configuring a 6to4 tunnel ········································································································· 251

Restrictions and guidelines ································································································ 251

Procedure ······················································································································ 251

6to4 tunnel configuration example ······················································································· 252

6to4 relay configuration example ························································································ 254

Configuring an ISATAP tunnel ·································································································· 257

Restrictions and guidelines ································································································ 257

Procedure ······················································································································ 257

Configuration example ······································································································ 258

IPv4 over IPv4 tunneling ································································ 261

Overview ······························································································································ 261

Configuring an IPv4 over IPv4 tunnel ························································································· 261

Restrictions and guidelines ································································································ 261

Procedure ······················································································································ 262

Configuration example ············································································································ 263

IPv4 over IPv6 tunneling ································································ 266

Overview ······························································································································ 266

Configuring an IPv4 over IPv6 tunnel ························································································· 266

Restrictions and guidelines ································································································ 266

Procedure ······················································································································ 267

Configuration example ············································································································ 267

IPv6 over IPv6 tunneling ································································ 271

Overview ······························································································································ 271

Configuring an IPv6 over IPv6 tunnel ························································································· 271

Restrictions and guidelines ································································································ 271

Procedure ······················································································································ 272

Configuration example ············································································································ 273

Configuring GRE ·········································································· 276

Overview ······························································································································ 276

GRE encapsulation format ································································································ 276

GRE tunnel operating principle ··························································································· 276

GRE application scenarios ································································································ 277

Protocols and standards ··································································································· 278

Configuring a GRE/IPv4 tunnel ································································································· 278

Configuration guidelines ··································································································· 278

Configuration procedure ··································································································· 279

Configuring a GRE/IPv6 tunnel ································································································· 280

Configuration guidelines ··································································································· 280

Configuration procedure ··································································································· 281

Displaying and maintaining GRE ······························································································· 282

GRE configuration examples ···································································································· 282

Configuring an IPv4 over IPv4 GRE tunnel ············································································ 282

Configuring an IPv4 over IPv6 GRE tunnel ············································································ 285

Troubleshooting GRE ············································································································· 287

Symptom ······················································································································· 287

Analysis ························································································································ 288

Solution ························································································································· 288

Configuring HTTP redirect ······························································ 289

About HTTP redirect ··············································································································· 289

HTTP redirect tasks at a glance ································································································ 289

Specifying the HTTPS redirect listening port number ····································································· 289

Associating an SSL server policy with the HTTPS redirect service ···················································· 290

x

Document conventions and icons ···················································· 291

Conventions ························································································································· 291

Network topology icons ··········································································································· 292

Support and other resources ·························································· 293

Accessing Hewlett Packard Enterprise Support ············································································ 293

Accessing updates ················································································································· 293

Websites ······················································································································· 294

Customer self repair ········································································································· 294

Remote support ·············································································································· 294

Documentation feedback ·································································································· 294

Index ························································································· 296

1

Configuring ARP

Overview

ARP resolves IP addresses into MAC addresses on Ethernet networks.

ARP message format

ARP uses two types of messages: ARP request and ARP reply. Figure 1 shows the format of ARP

request/reply messages. Numbers in the figure refer to field lengths.

Figure 1 ARP message format

• Hardware type—Hardware address type. The value 1 represents Ethernet.

• Protocol type—Type of the protocol address to be mapped. The hexadecimal value 0x0800

represents IP.

• Hardware address length and protocol address length—Length, in bytes, of a hardware

address and a protocol address. For an Ethernet address, the value of the hardware address

length field is 6. For an IPv4 address, the value of the protocol address length field is 4.

• OP—Operation code, which describes the type of ARP message. The value 1 represents an

ARP request, and the value 2 represents an ARP reply.

• Sender hardware address—Hardware address of the device sending the message.

• Sender protocol address—Protocol address of the device sending the message.

• Target hardware address—Hardware address of the device to which the message is being

sent.

• Target protocol address—Protocol address of the device to which the message is being sent.

ARP operating mechanism

As shown in Figure 2, Host A and Host B are on the same subnet. Host A sends a packet to Host B as

follows:

1. Host A looks through the ARP table for an ARP entry for Host B. If one entry is found, Host A

uses the MAC address in the entry to encapsulate the IP packet into a data link layer frame.

Then Host A sends the frame to Host B.

2. If Host A finds no entry for Host B, Host A buffers the packet and broadcasts an ARP request.

The payload of the ARP request contains the following information:

 Sender IP address and sender MAC address—Host A's IP address and MAC address.

 Target IP address—Host B's IP address.

 Target MAC address—An all-zero MAC address.

28-byte ARP request/reply

OP Sender hardware

address Sender protocol

address Target hardware

address Target protocol

address

Protocol

type

22 61 442 61

Hardware address length

Protocol address length

Hardware

type

2

All hosts on this subnet can receive the broadcast request, but only the requested host (Host B)

processes the request.

3. Host B compares its own IP address with the target IP address in the ARP request. If they are

the same, Host B operates as follows:

a. Adds the sender IP address and sender MAC address into its ARP table.

b. Encapsulates its MAC address into an ARP reply.

c. Unicasts the ARP reply to Host A.

4. After receiving the ARP reply, Host A operates as follows:

a. Adds the MAC address of Host B into its ARP table.

b. Encapsulates the MAC address into the packet and sends the packet to Host B.

Figure 2 ARP address resolution process

If Host A and Host B are on different subnets, Host A sends a packet to Host B as follows:

5. Host A broadcasts an ARP request where the target IP address is the IP address of the

gateway.

6. The gateway responds with its MAC address in an ARP reply to Host A.

7. Host A uses the gateway's MAC address to encapsulate the packet, and then sends the packet

to the gateway.

8. If the gateway has an ARP entry for Host B, it forwards the packet to Host B directly. If not, the

gateway broadcasts an ARP request, in which the target IP address is the IP address of Host B.

9. After the gateway gets the MAC address of Host B, it sends the packet to Host B.

ARP table

An ARP table stores dynamic, static, OpenFlow, and Rule ARP entries.

Dynamic ARP entry

ARP automatically creates and updates dynamic entries. A dynamic ARP entry is removed when its

aging timer expires or the output interface goes down. In addition, a dynamic ARP entry can be

overwritten by a static ARP entry.

Static ARP entry

A static ARP entry is manually configured and maintained. It does not age out and cannot be

overwritten by any dynamic ARP entry.

Static ARP entries protect communication between devices because attack packets cannot modify

the IP-to-MAC mapping in a static ARP entry.

The device supports the following types of static ARP entries:

Target IP

address

192.168.1.1

Target IP

address

192.168.1.2

Host A

192.168.1.1

0002-6779-0f4c

Host B

192.168.1.2

00a0-2470-febd

Target MAC

address

0000-0000-0000

Sender MAC

address

00a0-2470-febd

Target MAC

address

0002-6779-0f4c

Sender IP

address

192.168.1.1

Sender MAC

address

0002-6779-0f4c

Sender IP

address

192.168.1.2

3

• Long static ARP entry—It contains the IP address, MAC address, and one of the following

combinations:

 VLAN and output interface.

 Input and output interfaces.

A long static ARP entry is directly used for forwarding packets.

• Short static ARP entry—It contains only the IP address and MAC address.

 If the output interface is a Layer 3 Ethernet interface, the short ARP entry can be directly

used to forward packets.

 If the output interface is a VLAN interface, the device sends an ARP request whose target IP

address is the IP address in the short entry. If the sender IP and MAC addresses in the

received ARP reply match the short static ARP entry, the device performs the following

operations:

− Adds the interface that received the ARP reply to the short static ARP entry.

− Uses the resolved short static ARP entry to forward IP packets.

• Multiport ARP entry—It contains the IP address, MAC address, and VLAN.

The device can use a multiport ARP entry that has the same MAC address and VLAN as a

multicast or multiport unicast MAC address entry for packet forwarding. A multiport ARP entry is

manually configured. It does not age out and cannot be overwritten by any dynamic ARP entry.

For more information about multicast MAC, see IP Multicast Configuration Guide.

To communicate with a host by using a fixed IP-to-MAC mapping, configure a short static ARP entry

on the device. To communicate with a host by using a fixed IP-to-MAC mapping through an interface

in a VLAN, configure a long static ARP entry on the device.

OpenFlow ARP entry

ARP creates OpenFlow ARP entries by learning from the OpenFlow module. An OpenFlow ARP

entry does not age out, and it cannot be updated. An OpenFlow ARP entry can be used directly to

forward packets. For more information about OpenFlow, see OpenFlow Configuration Guide.

Rule ARP entry

ARP creates Rule ARP entries by learning from the portal, VXLAN, and OVSDB modules. A Rule

ARP entry does not age out, and it cannot be updated. It can be overwritten by a static ARP entry. A

Rule ARP entry can be used directly to forward packets.

For more information about portal, see Security Configuration Guide. For more information about

VXLAN and OVSDB, see VXLAN Configuration Guide.

Configuring a static ARP entry

Static ARP entries are effective when the device functions correctly.

A resolved short static ARP entry becomes unresolved upon certain events, for example, when the

resolved output interface goes down, or the corresponding VLAN or VLAN interface is deleted.

Long static ARP entries can be effective or ineffective. Ineffective long static ARP entries cannot be

used for packet forwarding. A long static ARP entry is ineffective when any of the following conditions

exists:

• The corresponding VLAN interface or output interface is down.

• The IP address in the entry conflicts with a local IP address.

• No local interface has an IP address in the same subnet as the IP address in the ARP entry.

A long static ARP entry in a VLAN is deleted if the VLAN or VLAN interface is deleted.

To configure a static ARP entry:

4

Step

Command

Remarks

1. Enter system view. system-view N/A

2. Configure a static ARP

entry.

• Configure a long static ARP entry:

arp static ip-address mac-address

[ vlan-id interface-type

interface-number | vsi-interface

vsi-interface-id tunnel number vsi

vsi-name | vsi-interface

vsi-interface-id interface-type

interface-number service-instance

instance-id vsi vsi-name ]

[ vpn-instance vpn-instance-name ]

• Configure a short static ARP entry:

arp static ip-address mac-address

[

vpn-instance

vpn-instance-name ]

By default, no static ARP entries

exist.

Configuring a multiport ARP entry

NOTE:

For multiport ARP entries to be effective for packet forwarding

, make sure the following conditions

exist:

•

A service loopback group is created to support the multiport ARP service.

•

The service loopback group has a minimum of one member port that is not used for any other

purposes and does not have any configuration.

For information about creating

and configuring a service loopback group, see Layer 2—LAN

Switching Configuration Guide.

A multiport ARP entry contains an IP address, MAC address, and VLAN ID.

To make the multiport ARP entry effective for packet forwarding, you must configure a multicast or

multiport unicast MAC address entry to specify multiple output interfaces. The MAC address entry

must have the same MAC address and VLAN ID as the multiport ARP entry. In addition, the IP

address in the multiport ARP entry must reside on the same subnet as the VLAN interface of the

specified VLAN.

A multiport ARP entry can overwrite a dynamic, short static or long static ARP entry. Conversely, a

short static or long static ARP entry can overwrite a multiport ARP entry.

To configure a multiport ARP entry:

Step

Command

Remarks

1. Enter system view. system-view N/A

2. Configure a multicast or

multiport unicast MAC

address entry.

• Configure a multiport unicast

MAC address entry:

mac-address multiport

mac-address interface

interface-list vlan vlan-id

• Configure a multicast MAC

address entry:

mac-address multicast

mac-address interface

interface-list vlan vlan-id

By default, no multicast or

multiport unicast MAC address

entries exist.

For more information about the

mac-address multiport

command, see Layer 2—LAN

Switching Command Reference.

For more information about the

mac-address multicast

command, see IP Multicast

Command Reference.

3. Configure a multiport

arp multiport ip-address

By default, no multiport ARP

5

Step

Command

Remarks

ARP entry.

mac-address vlan-id [ vpn-instance

vpn-instance-name ]

entries exist.

Setting the maximum number of dynamic ARP

entries for a device

A device can dynamically learn ARP entries. To prevent a device from holding too many ARP entries,

you can set the maximum number of dynamic ARP entries that the device can learn. When the

maximum number is reached, the device stops learning ARP entries.

If you set a value lower than the number of existing dynamic ARP entries, the device does not

remove the existing entries unless they are aged out.

To set the maximum number of dynamic ARP entries for a device:

Step

Command

Remarks

1. Enter system view.

system-view

N/A

2. Set the maximum

number of dynamic

ARP entries for the

device.

arp max-learning-number max-number slot

slot-number

By default, the maximum

number of dynamic ARP entries

that a device can learn depends

on the ARP table capacity set by

using the hardware-resource

switch-mode command. For

information about the

hardware-resource

switch-mode command, see

Fundamentals Command

Reference.

To disable the device from

learning dynamic ARP entries,

set the number to 0.

Setting the maximum number of dynamic ARP

entries for an interface

An interface can dynamically learn ARP entries. To prevent an interface from holding too many ARP

entries, you can set the maximum number of dynamic ARP entries that the interface can learn. When

the maximum number is reached, the interface stops learning ARP entries.

You can set limits for both a Layer 2 interface and the VLAN interface for a permitted VLAN on the

Layer 2 interface. The Layer 2 interface learns an ARP entry only when neither limit is reached.

The total number of dynamic ARP entries that all interfaces learn will not be larger than the maximum

number of dynamic ARP entries set for the device.

To set the maximum number of dynamic ARP entries for an interface:

Step

Command

Remarks

1. Enter system view. system-view N/A

2. Enter interface view. interface interface-type

interface-number N/A

6

Step

Command

Remarks

3. Set the maximum number

of dynamic ARP entries for

the interface.

arp max-learning-num

max-number [ alarm

alarm-threshold ]

By default, the maximum number of

dynamic ARP entries that an interface

can learn depends on the ARP table

capacity set by using the

hardware-resource switch-mode

command. For information about the

hardware-resource switch-mode

command, see Fundamentals

Command Reference.

To disable the interface from learning

dynamic ARP entries, set the number

to 0.

Setting the aging timer for dynamic ARP entries

Each dynamic ARP entry in the ARP table has a limited lifetime, called an aging timer. The aging

timer of a dynamic ARP entry is reset each time the dynamic ARP entry is updated. A dynamic ARP

entry that is not updated before its aging timer expires is deleted from the ARP table.

To set the aging timer for dynamic ARP entries:

Step

Command

Remarks

1. Enter system view. system-view N/A

2. Set the aging timer for dynamic

ARP entries. arp timer aging

{ aging-minutes | second

aging-seconds } The default setting is 20 minutes.

Enabling dynamic ARP entry check

The dynamic ARP entry check feature disables the device from supporting dynamic ARP entries that

contain multicast MAC addresses. The device cannot learn dynamic ARP entries containing

multicast MAC addresses. You cannot manually add static ARP entries containing multicast MAC

addresses.

When dynamic ARP entry check is disabled, ARP entries containing multicast MAC addresses are

supported. The device can learn dynamic ARP entries containing multicast MAC addresses obtained

from the ARP packets sourced from a unicast MAC address. You can also manually add static ARP

entries containing multicast MAC addresses.

To enable dynamic ARP entry check:

Step

Command

Remarks

1. Enter system view. system-view N/A

2. Enable dynamic ARP entry

check. arp check enable By default, dynamic ARP entry check is

enabled.

Synchronizing ARP entries

This task ensures that all IRF member devices have the same ARP entries.

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To synchronize ARP entries across all member devices in a timely manner, you can schedule the

master device to automatically execute the arp smooth command. For information about scheduling

a task, see Fundamentals Configuration Guide.

To synchronize ARP entries from the master device to all subordinate devices:

Task

Command

Synchronize ARP entries from the master device to

all subordinate devices. arp smooth

Configuring a customer-side port

By default, the device associates an ARP entry with routing information when the device learns an

ARP entry. The ARP entry provides the next hop information for routing. To save hardware resources,

you can use this command to specify a port that connects a user terminal as a customer-side port.

The device will not associate the routing information with the learned ARP entries.

To configure a customer-side port:

Step

Command

Remarks

1. Enter system view. system-view N/A

2. Enter interface view. interface interface-type

interface-number N/A

3. Configure the VLAN

interface as a

customer-side port. arp mode uni By default, a port operates as a

network-side port.

Enabling ARP logging

This feature enables a device to log ARP events when ARP cannot resolve IP addresses correctly.

The device can log the following ARP events:

• On a proxy ARP-disabled interface, the target IP address of a received ARP packet is not one of

the following IP addresses:

 The IP address of the receiving interface.

 The virtual IP address of the VRRP group.

• The sender IP address of a received ARP reply conflicts with one of the following IP addresses:

 The IP address of the receiving interface.

 The virtual IP address of the VRRP group.

The device sends ARP log messages to the information center. You can use the info-center source

command to specify the log output rules for the information center. For more information about

information center, see Network Management and Monitoring Configuration Guide.

To enable the ARP logging feature:

Step

Command

Remarks

1. Enter system view. system-view N/A

2. Enable the ARP logging

feature. arp check log enable By default, ARP logging is disabled.

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Displaying and maintaining ARP

IMPORTANT:

Clearing ARP entries from the ARP table

might cause communication failures.

Make sure the entries

to be cleared do not affect current communications.

Execute display commands in any view and reset commands in user view.

Task

Command

Display ARP entries. display arp [ [ all | dynamic | multiport | static ] [ slot

slot-number ] | vlan vlan-id | interface interface-type

interface-number ] [ count | verbose ]

Display the ARP entry for an IP address. display arp ip-address [ slot slot-number ] [ verbose ]

Display the maximum number of ARP

entries that a device supports. display arp entry-limit

Display the number of OpenFlow ARP

entries. display arp openflow count [ slot slot-number ]

Display the ARP entries for a VPN

instance. display arp vpn-instance vpn-instance-name [ count ]

Display the aging timer of dynamic ARP

entries. display arp timer aging

Clear ARP entries from the ARP table. reset arp { all | dynamic | interface interface-type

interface-number | multiport | slot slot-number | static }

Configuration examples

Long static ARP entry configuration example

Network requirements

As shown in Figure 3, hosts are connected to Device B. Device B is connected to Device A through

interface Ten-GigabitEthernet 1/0/1 in VLAN 10.

To ensure secure communications between Device A and Device B, configure a long static ARP

entry for Device A on Device B.

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Aruba Layer 3—IP Routing Configuration Guide

Aruba Layer 3—IP Routing Configuration Guide

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