Draytek 2820 to ASA 5510 duplicate Phase1 packet detected
I have a really strange situation. For one of our customers I had to configure a Draytek dsl router to connect to their ASA 5510 at HQ location.
When I configure this, the tunnel doesn't come up. It even doesn't pass Phase1 but gives 2 errors:
duplicate phase1 packet detected
p1 retransmit msg dispatched to MM FSM
Whatever I try, different settings of encryption, lifetimes, Nat-T settings, on both ends, it always ends up like this.
Note: This ASA has already 10 ipsec tunnels to similar Drayteks (the customer runs stores troughout the country, puts a Draytek in every store and asks me to configure the Cisco ASA side. No problem, until today, with the 11th Draytek.
Strange thing is, that when I setup a tunnel from the Draytek to our testlab ASA(5520) there is no problem and the tunnel comes up! Same settings, only this 5520 runs 8.2.2(17) software and the 5510 runs on 8.2.5
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...