Nortel Networks 620 User Manual

Page of 222
Chapter 3
Configuration via Local Pages
E-DOC-CTC-20051017-0169 v0.1
68
Miscellaneous
Comprises the following settings:
IKE Exchange Mode:
IKE specifies two modes of operation for the Phase 1 negotiations: main mode 
and aggressive mode. Main mode is more secure while aggressive mode is 
quicker.
Primary Untrusted Physical Interface:
This field shows a list of your SpeedTouch™ interfaces. You select the 
preferred Primary Untrusted Physical Interface. This interface is used as the 
primary carrier for your VPN connection. In general, the primary untrusted 
interface is your DSL connection to the public Internet.
In the SpeedTouch™ the routing engine determines which interface is used for 
the VPN connection (your DSL connection to the Internet in most cases). So, 
what is the relevance to select a physical interface? 
The VPN server handles incoming VPN connections only. For this kind of 
connections, where your SpeedTouch™ is the responder in the IKE 
negotiations, the interface is part of the matching process for accepting the 
connection. Using the default setting (any) has the effect of removing this 
matching criterion. For a VPN server configuration, this is the most convenient 
setting. If you select a specific interface as Primary Untrusted Physical 
Interface
, then a 
new
 incoming VPN connection on a 
backup
 
interface
 is not 
accepted.
The SpeedTouch™ VPN server has no mechanism for re-routing active VPN 
connections to a backup physical interface. Even if your SpeedTouch™ is 
equipped with an ISDN backup interface, all active VPN connections are lost 
when the primary interface of the VPN server fails. The overall network 
topology determines whether a VPN client is capable of reaching the backup 
interface of the SpeedTouch™ VPN server. It is the responsibility of the VPN 
client to set up a new VPN connection.
Inactivity Timeout:
When no traffic is detected at the peer for a certain period, it is decided that the 
tunnel is not used any more, and the IKE session is terminated. All IPSec 
connections supported by the IKE session are terminated as well.
This option sets the value of the inactivity timer.
Inactivity Timeout
default value
seconds
3600