Exchange can't receive external emails

We have exchange 6.5 and are having problem receiving external emails.  We can send external and internal emails, receive internal emails, but can't receive external emails.  I ran a check on the domain at  It passed everything except we had 1 error.

    Error connecting to mail server [] port 25 : timed out waiting for connection

  Any ideas?
cntechNetwork ManagerAsked:
Who is Participating?
That means what it says - the testing server was unable to connect to your server.
You need to see where the block is taking place, so internally look to see whether the SMTP service is running, whether you can telnet to port 25. Then look at your firewall to ensure that SMTP port 25 is open and pointing at the correct internal IP address. Finally check with your ISP to ensure that the port hasn't been blocked over the weekend.

Simon,  Hitting the Nail on the Head again!!

If you want to know what your mail address is go to your mail server and from IE goto

Then you can start on the router/firewall/NAT that seems like the problem....

Simon,   Get some rest...   :)

First of all is this a recent problem? Was it working previously?

You are able to send out mail as you may be using DNS for name resolution or a smarthost.

Test telnet internally first you may do either on the server or via workstation:
See: basic testing area.

If you are able to connect then move to testing the gateway. I would

1. First logonto the server run a scan port  i have used in the past if your firewall/router is not operating in s stealth mode you should be able to see what ports are actually open inbound.
2. Depending on the outcome logonto your firewall/router and check either the port redirection or the firewall setting as Simon has suggested.


cntechNetwork ManagerAuthor Commented:
This is a recent problem, as it previously worked.
cntechNetwork ManagerAuthor Commented:
After looing into this, the mx record was messed up, after we changed it everything worked.

   Thanks for you ideas.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.