Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

1761 static PAT configuration problem

Hi, I have been trying to configure a static PAT on a 1761 router to get to an SMTP server behind this router. I have configured it, but when I am trying to telnet to the IP address of the router (public) on port 25 I do not get anywhere, even though the log on the router shows that NAT is working.

.Apr 21 11:22:11: NAT: o: tcp (x.x.x.x, 1807) -> (y.y.y.y, 25) [44453]

.Apr 21 11:22:11: NAT: s=x.x.x.x, d=y.y.y.y-> [44453]

.Apr 21 11:22:11: %SEC-6-IPACCESSLOGP: list 191 permitted tcp -> x.x.x.x(1807), 1 packet

.Apr 21 11:22:11: NAT: i: tcp (, 25) -> (x.x.x.x, 1807) [16029]

.Apr 21 11:22:11: NAT: s=>y.y.y.y, d=x.x.x.x[16029]

x.x.x.x - my IP address, y.y.y.y - public IP of the router, - the server I am trying to get to.

1761 IOS version is 12.3(5b)

I have attached the diagram of the network and the configuration of the router. Could someone help me please, as this issue is really driving me mad... :)

New Member

Re: 1761 static PAT configuration problem


New Member

Re: 1761 static PAT configuration problem

Ah yes ACL on the WAN interface allows all TCP connections on port 25 through.

If there are any questions - please ask.

Any takers?

New Member

Re: 1761 static PAT configuration problem

Got it :)

CBAC was blocking traffic from the internal mail server to outside on the outside interface :)