Lancom Systems 1621 User Manual

Page of 82
LANCOM 821 ADSL/ISDN – LANCOM 1621 ADSL/ISDN – LANCOM 1711 VPN
 Chapter 5: Linking two networks
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EN
5 Linking two networks
With the network interconnection (also known as LAN to LAN coupling) of the
LANCOM, two local networks are linked. The LAN to LAN coupling can be
realized in principle in two different ways:
Only LANCOM 
1621 ADSL/ISDN 
and LANCOM 1711 
VPN
VPN: For coupling via VPN, the connection between both LANs is estab-
lished over a specially secured connection through the public Internet. A
router with VPN support is required in both LANs.
ISDN: For coupling via ISDN, a direct connection between both LANs is
established over an ISDN connection. A router with ISDN interface is
required in both LANs.
Always configure both sides 
Both routers involved in the network interconnection must be configured.
Care  must  be  taken  to  ensure  that  the configuration information provided
matches.
The following instructions will assume that LANCOM routers are being
used on both sides. A network interconnection may also be realized
with routers from other manufacturers. A mixed setup usually requires
more extensive configuration measures for both devices, however.
Please refer to the reference manual for more information in this
regard. 
A setup wizard handles the configuration of the connection in the usual con-
venient manner. 
Security aspects 
You must, of course, protect your LAN against unauthorized access. A
LANCOM therefore offers a whole range of security mechanisms that can pro-
vide an outstanding level of protection:
VPN: Network couplings via VPN transmit data by IPSec. The data are
encrypted by  AES, 3-DES, Blowfish or CAST encryption algorithms. 
ISDN: For network couplings via ISDN, the connection password, the
checking of the ISDN number and the callback function ensure the secu-
rity of the connection.