I have a handful of 871's for SOHO users which started out utilizing an EZVPN tunnel back to an ASA at our headquarters location. That was extremely unstable so it has now been flipped to a static to dynamic mapping in the default L2L tunnel group and I'm see similar results. I've tried isolating the issues with no luck.
I've added an attachment with the error messages I see consistently. It seems as though the ASA 5520 just stops responding.
I've messed with the tcp mss values clearing the df-bit and also tried some of the timers but nothing seems to work.
Sometimes the tunnel stays up for hours other times it drops after 5 minutes. One thing that is consistent is that it drops multiple times per day.
Any assistance would be greatly appreciated.