connections over VPN stop working unless I manually restart it

Question

I have a site to site VPN set up with a vendor. I can hit the remote servers consistently for about 2 weeks, and then all new connection attempts time out. No ping, no http, nothing. If I go into my firewall config and turn off the VPN and then turn it back on, the connections begin working again.

I have a number of other VPNs set up that don't have this problem, so I'm thinking this is either an issue with the remote server and/or firewall. What things should I try to fix this?

Solution

We've seen that happen too. Have you looked at the IKE dead peer detection on the advanced screen on your Sonicwall? Basically the idea behind this is that if it missed so many heartbeats it will assume the IKE peer is DOA and disconnect. Keep an eye on your logs, odds are the other side is rebooting their FW or there is an interuption between you and your vendor.

Comments

[Fergus]

Do you have a firewall session log for when you attempt to tunnel?

[Driftpeasant]

It's also possible that it's not automatically rekeying properly. I've seen that happen a number of times - and it always seems to happen when the re-key intervals are slightly off - so for some period of time it'll accept the time drift, then one device will stop re-keying and you have to reset.