Thanks to Marc and Ron. My understanding is a packet which reaches the IOS intially passes thru the ACL and then thru the CBAC. As disabling the "ip inpect" makes the AUTH work, it can't be the problem with the port 113. I will shed more light on this. The CBAC is enabled on f0/0,f0/1 and s0/0. Disabling SMTP inspection on all the ports allowed our Interport AUTH work. Supposing that our Exchange server is on f0/0, disabling SMTP inspection on both f0/0, f0/1 allowed the AUTH traffic to pass on. Moreover ACL was only enabled on s0/0. I think now you have a clear picture.
Marc ---- At first glance I was about to dump this as being an OT mail (Exchange = server) issue however, I seem to recall a similar problem some time ago. I think the reason why your internal email is getting bounced is because = when IDENT/auth lookups (port 113 udp/tcp authentication) are enabled, = your firewall is probably denying the IDENT lookups to your internal = hosts. Check for the rejected port 113 traffic to your internal hosts in your = syslog, this should clear things up.. Cheers.. Marc >>> "Prathabacimman.M" <[EMAIL PROTECTED]> 01/07 9:56 PM >>> Thanks to Henry Sieff Adding more to the above problem yesterday we solved the problem but=20 temporarily. As we remove "ip inspect name 'name' smtp" things have = started moving smoothly. But our situation forces us to implement smtp monitoring. How to go about it.. Prathabacimman.M (call me prathab) Hi,=20 I have a got a very peculiar problem with Cisco IOS Firewall 21.4 on Cisco 2621 Router. Our mail server recides on the DMZ and We have got CBAC and Access lists enabled on the Router. There's no problem with the traffic except SMTP. When the authentication is enabled for SMTP relay on our Exchange Server, the internet clients are unable to send mails thru the server. The mails get bounced. When the authentication is removed the = server is vulnerable to open relay. There's certainly a problem with the=20 router/image/CBAC/ACL but we cannot identify where it lies. Can any one = help me in troubleshooting.=20 Prathabacimman.M=20 _______________________________________________ _______________________________________________ Firewalls mailing list [EMAIL PROTECTED] http://lists.gnac.net/mailman/listinfo/firewalls
