Weird problem here. I have a Site-to-Site VPN that isn't working. Both ASAs have other Site-To-Site VPNs working on them. I know the configuration is correct because it was working fine for months and it hasn't changed.
I have both a successful Phase 1 and Phase 2 but both sides don't show any return traffic. When I do an ASP drop capture at the HQ, I see it dropping ESP packets from an unknown IP. These packets have to be coming from the remote side though because when I reboot the reboot ASA, the packets stop dropping. As soon as the ASA comes back up, I start seeing the packets drop again.
When I do a capture at the remote side, I see it dropping ESP packets from an unknown IP as well. This side also has a successful Phase 1 and Phase 2 but doesn't see any return traffic either.
Any ides on what might be causing this?