[c-nsp] vpn down if no traffic

[Justin M. Streiner]

On Thu, 8 Feb 2007, Alexandre Durand wrote:

> I m wondering why with any cisco router, vpn tunnel site to site goes
> down if no traffic is generated. Is there a timeout somewhere we can
> configure or remove? is there a way to maintain this vpn tunnel up even
> if there is no traffic?

This is normal behavior.  You're either running into an IKE or IPSEC 
timeout (data or time).  The tunnel should immediately re-establish when 
the router sees traffic that would want to go into the tunnel.  I don't 
believe the timers can be disabled.  Re-establishing a site to site VPN 
tunnel is prett painless and normally automatic, so it shouldn't be a big 
issue.

If you really wanted to, I suppose you could set up a machine on one side 
of the tunnel to ping a machine on the other side once every few minutes 
or so, but keep in mind that at some point the tunnel will still reach a 
point where it has to drop and re-key, then come back up.

jms