8
Features
DHCP server and a DNS server will
take over IP address administration
and name resolution for the client
PCs.
The OpenCom 510 enables all con-
nected PCs to access the Internet
using a common IP address; only the
common address will be visible out-
side the LAN. Network address trans-
lation (NAT) is used to change the IP
addresses of the local (client) PCs
into the IP address of the
OpenCom 510. This prevents direct
access to the LAN’s client PCs and
thus offers protection against at-
tacks from the Internet. The
OpenCom 510 offers further protec-
tion of the LAN in the form of cus-
tomisable filter lists (firewall func-
tion).
Note: Also observe the notes in
Useful Information on Internet Access
starting on page 95.
DECT Data Communication
PCs that are not connected to the
OpenCom 510 via the internal S
0
ports or the Ethernet interface can
access the Internet if used in combi-
nation with a USB DECT Box or the
OpenPhone 25 DECT terminals. PCs
in these configurations can also
make full use of the Internet and e-
mail features of the OpenCom 510.
Data will then be transmitted via the
internal data interface of the
OpenPhone 25, which must be con-
nected to the serial port of the PC by
means of the supplied adapter. The
Internet can be accessed directly via
the remote data transfer (i.e. dial-
up) network. The OpenPhone 25 will
establish a data connection with the
OpenCom 510 via the DECT air inter-
face. The Internet connection itself
will be established either directly
through an ISDN B-channel or indi-
rectly through the internal RAS in-
terface of the OpenCom 510. Indi-
rect RAS access is preferable as it
uses the routing function of the
OpenCom 510 and thus benefits
from the security features of shared
Internet access.
The optional USB DECT Box enables
a PC to establish a wireless (DECT)
ISDN data connection. The USB DECT
Box and the PC are connected by
means of the USB interface.
For detailed information on install-
ing the required driver software and
on the various configuration op-
tions, refer to USB DECT Box on the
OpenCom 510 starting on page 135
and to the “OpenPhone 25” user
guide. For information on configur-
ing the OpenPhone 25 data inter-
face, please refer to the
OpenCom 510 online help.
E-Mail
The OpenCom 510 offers an inte-
grated e-mail function that supports
the POP3, APOP or IMAP4 protocols
used to query an Internet service
provider for incoming mail. The
OpenCom 510 can be configured to