Netopia 3346N-ENT User Guide (en)

Internet Key Exchange (IKE) IPsec Key Management for VPNs   6-9
Traffic based Dead Peer Detection
The default is No. Toggling this option to Yes allows IKE to negotiate RFC3706-based IKE “keepalives” with 
a remote security gateway (IKE peer) that suppor ts them.
If this feature is enabled and negotiated with its peer, keepalive messages are sent when:
the IPSec link has not received anything in DPD Keepalive Idle Time seconds (see below), and
some IPSec traffic is sent, and
one second passes with no IPSec traffic having been received.
If the IKE peer suppor ts the keepalives, the tunnel will reset to allow for reestablishment when the peer 
does not respond to the keepalive.
This permits the router to maintain its IPSec session without the requirement of constant keep alive traffic. 
Determination of peer liveliness is only needed during idle periods, since tunneled traffic is itself evidence 
of liveliness. Once enabled and negotiated, all tunnels established by the IKE phase 1 instance when the 
peer no longer responds to IKE keepalive messages will be killed.
When you enable this option, the next option, DPD Keepalive Idle Time (seconds), appears.
DPD Keepalive Idle Time (seconds) allows you to specify an inter val, from 3 to 65535 seconds, during 
which IPSec traffic may be idle before the router sends a keepalive message to its peer. The default is 20 
Changing an IKE Phase 1 Profile
To make changes to an IKE Phase 1 Profile, select IKE Phase 1 Configuration from the WAN Configuration 
menu, and press Return.
                                WAN Configuration
                     WAN (Wide Area Network) Setup...
                     Display/Change Connection Profile...
                     Add Connection Profile...
                     Delete Connection Profile...
                     ATMP/PPTP Default Profile...
                     IKE Phase 1 Configuration...
                     Advanced Connection Options...
Return/Enter to configure IPSec tunnel configuration options.
From here you will configure yours and the remote sites' WAN information.