?
Solved

SMTP port to remote Exchange Server is blocked

Posted on 2010-11-19
12
Medium Priority
?
348 Views
Last Modified: 2012-05-10
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?
0
Comment
Question by:B1izzard
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 3
  • 2
  • +1
12 Comments
 
LVL 15

Expert Comment

by:getzjd
ID: 34175053
Are you sure the other server is actually an exchange server and not a spam appliance or filtering device?
0
 
LVL 31

Expert Comment

by:MegaNuk3
ID: 34175061
Have you pinged the server from both locations to see if the same IP address is returned?
0
 
LVL 76

Expert Comment

by:Alan Hardisty
ID: 34175070
Does it show No banner at all or something like:

220 ***************************************************************************
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 15

Expert Comment

by:getzjd
ID: 34175075
If it were blocked by the firewall specifically, then you should not even be making any type of initial connection.
0
 
LVL 31

Expert Comment

by:MegaNuk3
ID: 34175102
Pinger = pinged
Stupid iPhone autospell...
0
 
LVL 76

Expert Comment

by:Alan Hardisty
ID: 34175115
Consider it corrected : )
0
 

Author Comment

by:B1izzard
ID: 34175215
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...Could not open connection to the host, on port 25
: 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?
0
 
LVL 76

Expert Comment

by:Alan Hardisty
ID: 34175228
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?
0
 
LVL 76

Accepted Solution

by:
Alan Hardisty earned 1000 total points
ID: 34175349
This is what I see:

220 domain.org Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at  Fri
, 19 Nov 2010 10:39:55 -0800

That says to me that they are blocking you specifically.  Time to talk to their IT department.
0
 
LVL 15

Assisted Solution

by:getzjd
getzjd earned 1000 total points
ID: 34175351
Yes, sounds like you are being manually blocked then.  This is the information we needed to see.
0
 

Author Closing Comment

by:B1izzard
ID: 34278182
Thanks.
0

Featured Post

Get your Conversational Ransomware Defense e‑book

This e-book gives you an insight into the ransomware threat and reviews the fundamentals of top-notch ransomware preparedness and recovery. To help you protect yourself and your organization. The initial infection may be inevitable, so the best protection is to be fully prepared.

Question has a verified solution.

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

A list of top three free exchange EDB viewers that helps the user to extract a mailbox from an unmounted .edb file and get a clear preview of all emails & other items with just a single click on mailboxes.
After hours on line I found a solution which pointed to the inherited Active Directory permissions . You have to give/allow permissions to the "Exchange trusted subsystem" for the user in the Active Directory...
Established in 1997, Technology Architects has become one of the most reputable technology solutions companies in the country. TA have been providing businesses with cost effective state-of-the-art solutions and unparalleled service that is designed…
There are cases when e.g. an IT administrator wants to have full access and view into selected mailboxes on Exchange server, directly from his own email account in Outlook or Outlook Web Access. This proves useful when for example administrator want…
Suggested Courses

771 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