I have problems with an ASA 5510 and GRE.
I can't make a gre tunnel from the inside network to a host on the internet. I only get to the part where I have to enter the username and password and there it breaks. I get a teardown gre connection in the logs exactly after 30 sec.
The inside network and outside network both have real ip addresses so I have no NAT configured and no need for NAT.
I tried fixup protocol pptp 1723 and inspect pptp.
The ACLs allow both gre and tcp 1723 both on the outside and on the inside (I also tried with allow ip any any to be sure it's not ACL related).