Site to Site VPN Tunnel Disconnect with Router Reboot

[pshelfo1]

I recently upgraded a remote office 1720 router with a newer IOS. I have a PIX 515 firewall behind the router that establishes a site to site VPN with a VPN 3015 conectrator at headquarters.

When the 1720 router reboots the VPN site-to-site tunnel never re-establishes automatically. If I ping accross the 1720 router interfaces while on the PIX console the tunnel establishes. I thought the PIX would take care of the tunnel re-establishment?

[wong.jason]

Try setting the ISAKMP keepalive on the PIX.

Should fix the problem.

[pshelfo1]

Thanks. That makes sense. What is a good value to set to?

isakmp keepalive 30 ???