B1izzard
asked on
SMTP port to remote Exchange Server is blocked
We've been having issues receiving email from a specific Exchange server to our Exchange server. Neither server has problems sending to any other server, so this appears isolated.
One thing I noticed is that when running telnet mail.remotedomain.org 25, it does not show any banner. When running netstat it shows SYN_Sent from our server to theirs, but never completes the handshake. From another location, I can telnet ok to the mail.remotedomain.org server just fine.
What might be causing this problem? I can only imagine it is being blocked by the firewall or the IP is being denied by Exchange. I don't have access to the server unfortunately. Anyone have any ideas on what might be causing this?
One thing I noticed is that when running telnet mail.remotedomain.org 25, it does not show any banner. When running netstat it shows SYN_Sent from our server to theirs, but never completes the handshake. From another location, I can telnet ok to the mail.remotedomain.org server just fine.
What might be causing this problem? I can only imagine it is being blocked by the firewall or the IP is being denied by Exchange. I don't have access to the server unfortunately. Anyone have any ideas on what might be causing this?
getzjd
Are you sure the other server is actually an exchange server and not a spam appliance or filtering device?
Have you pinged the server from both locations to see if the same IP address is returned?
Does it show No banner at all or something like:
220 **************************
220 **************************
If it were blocked by the firewall specifically, then you should not even be making any type of initial connection.
Pinger = pinged
Stupid iPhone autospell...
Stupid iPhone autospell...
Consider it corrected : )
ASKER
Here is the banner from a know good location:
220 remotedomain.org Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Fri
, 19 Nov 2010 10:14:51 -0800
When telnetting from the problem location to the remote server, it gives:
Connecting To mail.remotedomain.org...Co
: Connect failed
The same IP is returned in both locations, so DNS is not an issue.
I can't think of anything other than the firewall blocking, or Exchange blocking by ip. Anyone think any differently?
220 remotedomain.org Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Fri
, 19 Nov 2010 10:14:51 -0800
When telnetting from the problem location to the remote server, it gives:
Connecting To mail.remotedomain.org...Co
: Connect failed
The same IP is returned in both locations, so DNS is not an issue.
I can't think of anything other than the firewall blocking, or Exchange blocking by ip. Anyone think any differently?
It does sound like they are blocking you.
Can you test from another location or would you like one of us to test for you?
Can you test from another location or would you like one of us to test for you?
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ASKER
Thanks.