Site-to-Site VPN routing?

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Cisco ASA 8, ASDM 6.

I set up a IPSEC shared secret VPN with a customer.

The tunnel comes up fine, but I do not believe that any traffic is crossing it.

Pings fail, etc.

Looking at the log, I see the tunnel come up. Phase 1 and 2 successful.

Is there a trick to get the traffic to flow across the VPN??

Please advise, I am at my wits end on this one.


Re: Site-to-Site VPN routing?

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A common problem in such cases would be a mismatch between the
NAT definitions and the tunnel access-list definitions. The access
lists defined for the tunnel must be written in terms of what
would be on the wire *after* NAT takes place (for outgoing packets)
or before NAT takes place (for incoming packets).

Another issue is that listing traffic in a tunnel access-list
does not automatically permit the traffic through the outside
access group. After the traffic has been de-encapsulated, but
before it is de-NAT'd, the interface access group 'in' is checked,
and only traffic that passes the access-group is permitted inward.
However, there is a command you can use that will permit this
access-group check to be bypassed for *all* traffic that arrives
via VPN.

In PIX 6, the command was

sysopt connection permit-ipsec

I see that by ASA 8, it is

sysopt connection permit-vpn

Re: Site-to-Site VPN routing?
Walter Roberson wrote:
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Cisco has a document that deals with NAT Order of Operations. Might be
good to refer to it.

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If you use the following as the last ACE (Access Control Entry) in your
interface ACLs:

deny ip any any log

... and examine the resulting syslog entries, you might get a better
handle on any ACL issues that exist.

Crypto ACLs need to be exactly mirrored, without exceptions.

If you can get a sniffer on the WAN side of your device, you might very
quickly determine if you have asymmetric operation as a result of crypto
ACLs not being correctly mirrored. Some traffic that you expect to be
encrypted, would not be, and it gets dropped.

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Best Regards,
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