Cannot establish site-site vpn tunnel through ASA 9.1(2)

Question

Hi,
We use ASA 9.1(2) to filter traffic in/out of our organisation. A dept within the organisation also have a firewall. They want to establish a site-site VPN tunnel with a remote firewall. We have allowed full access between the public address of the dept firewall and the remote firewall and full access between the remote firewall address and the dept firewall address . We do not use NAT.
The site-site VPN tunnel fails to establish.
The dept sysadmin has requested that we enable IPSec Passthrough. From my reading this will not make any difference as we allow full access between the firewalls in both directions. Is that correct?
Has anyone encountered issues with ASA 9.1(2) interfering with site-site tunnels?
Regards

Answer 1

>The dept sysadmin has requested that we enable IPSec Passthrough. From my reading this will not make any difference as we allow full access between the firewalls in both directions. Is that correct?
Yes, in that case, no IPsec-pass-through is needed. All you need is (in both directions):
UDP/500
UDP/4500 (also if you don't use NAT, the remote gateway could be located behind a NAT gateway)
IP/50
for testing ICMP/Echo
If you allowed full IP-access between these two endpoints, it is more than enough.
When they start testing, do you see a connection on your ASA. There should be at least UDP/500 traffic.
Can the two gateways ping each other?