After a long while of searching and testing I managed to get Mikrotik <-> Racoon on Linux 2.6.25 working with rsa-sig and certificates. The error messages I got with racoon initially looked like the ones I had with the Cisco routers, so I assume the problem was the same. I will test again with Cisco...

Hi I am trying to build an IPSec tunnel to a Cisco using certificates instead of the usual pre-shared keys. What I end up with is: 00:03:18 ipsec IPsec-SA request for 192.168.0.20 queued due to no phase1 found. 00:03:18 ipsec initiate new phase 1 negotiation: 192.168.0.23[500]<=>192.168.0.20[500] 00...