Solved

ASA PAT works for incoming SMTP but not outgoing

Posted on 2009-07-02
4
1,121 Views
Last Modified: 2013-11-30
We had an exchange server on our internal 10.x.x.8 and external x.x.x.194 recently we installed a Cisco Ironport Anti-Spam appliance at internal 10.x.x.29 which needs SMTP traffice directed towards it but other protocols still going to 10.x.x.8 so I created a few PAT rules on the ASA to do this. I've confirmed everything coming from the outside in is directed to the correct machine but when the Ironport sends email it's sending it via the wrong external address x.x.x.195

I don't know if I need to specify Ironport to send mail ONLY on port 25 (thus forcing to follow the PAT) if so I don't know how to do that in the Ironport.

Or if there's some way in the ASA to force the Ironport appliance mail through the 194 external IP.


Here are the related config entries from the ASA.
global (outside) 1 interface

global (outside) 2 x.x.x.194 netmask 255.0.0.0

nat (inside) 0 access-list inside_outbound_nat0_acl

nat (inside) 1 0.0.0.0 0.0.0.0
 
 

access-list 100 extended permit ip any any inactive

access-list 100 extended permit tcp any host x.x.x.194 eq www

access-list 100 extended permit tcp any host x.x.x.194 eq 3389

access-list 100 extended permit tcp any host x.x.x.194 eq smtp
 

static (inside,outside) tcp 63.225.3.194 www 10.x.x.8 www netmask 255.255.255.255

static (inside,outside) tcp 63.225.3.194 3389 10.x.x.8 3389 netmask 255.255.255.255

static (inside,outside) tcp 63.225.3.194 smtp 10.x.x.29 smtp netmask 255.255.255.255

Open in new window

0
Comment
Question by:rguadiana
  • 2
  • 2
4 Comments
 
LVL 79

Expert Comment

by:lrmoore
ID: 24768144
If you can set the Ironport to send mail using a source port of anything other than port 25, that'll be all you need.
Else, you can just change your dns MX record to be the 194 external IP
0
 

Author Comment

by:rguadiana
ID: 24768167
I think the Ironport IS using a source port other than 25 which is causing it to use the dynamic PAT on the ASA and using the 195 ip. Our dns MX record is already set to 194, that's why I need the Ironport to send mail through port 25 and IP 194.
0
 
LVL 79

Accepted Solution

by:
lrmoore earned 125 total points
ID: 24768476
Aha... OK..

Access-list IRONPORT permit tcp host 10.x.x.29 any eq smtp
nat (inside) 2 access-list IRONPORT
0
 

Author Closing Comment

by:rguadiana
ID: 31599374
Thanks very much! worked like a charm
0

Featured Post

What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Hello Friends, My friends and relatives always ask me how to delete all the various types of emails at once in our g-mail  or windows live account.  So I researched this topic to find a unique solution to this query.  Here it is for those who do …
Exchange server is not supported in any cloud-hosted platform (other than Azure with Azure Premium Storage).
This is a video describing the growing solar energy use in Utah. This is a topic that greatly interests me and so I decided to produce a video about it.
The Email Laundry PDF encryption service allows companies to send confidential encrypted  emails to anybody. The PDF document can also contain attachments that are embedded in the encrypted PDF. The password is randomly generated by The Email Laundr…

919 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

24 Experts available now in Live!

Get 1:1 Help Now