?
Solved

Client change email port to 2525, now we can't send to them....How can we now?

Posted on 2007-04-11
8
Medium Priority
?
243 Views
Last Modified: 2010-03-06
Hi,

We have a small client who uses an ISP for their email services.  One day they decided to change the mail port from 25 to 2525 to try to stop spam.  Well, since they've done this many folks (Us included) have been unable to send to them.  We just figured this out by chance and then called the client to verify.  Telnetting to port 25 of the server yields nothing now since their ISP is now blocking that.  Now, the question is how can I configure our Exchange 2003 server to send email to this particular domain over port 2525 without causing issues with the thousands of others we send to?

TIA

Al
0
Comment
Question by:alchik
[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
  • 3
  • 2
8 Comments
 
LVL 31

Accepted Solution

by:
LeeDerbyshire earned 500 total points
ID: 18890182
You can change the port number in Exchange System Manager by looking at the properties of the Default SMTP Virtual Server, and clicking the Advanced button.  That will allow you to send to this one client, but when everyone else is using port 25, you won't be able to send to anyone else.  The rest of the world assumes that SMTP servers listen on port 25 - they can't keep trying every port to discover the changed port number.  If they can't connect on port 25 they will just give up.
0
 
LVL 104

Expert Comment

by:Sembee
ID: 18890230
The client needs to change their port back to 25. They cannot expect everyone who emails them to use another port. Asking Hotmail, AOL or any other major ISP to comply will be met with a polite no at best and a laugh at worst.

You cannot deal with spam by simply changing the port.

Simon.
0
 
LVL 1

Author Comment

by:alchik
ID: 18892168
The client has no control over the ISP changing the port unfortunately.  After doing some googling it seems others are doing this as well.  I was sort of hoping there was a way of routing domain specific traffic to say, a specific connector/virtual server what would send out via 2525.  
They say there are receiving email from some people.  I can send to them from gmail and yahoo.
0
NFR key for Veeam Backup for Microsoft Office 365

Veeam is happy to provide a free NFR license (for 1 year, up to 10 users). This license allows for the non‑production use of Veeam Backup for Microsoft Office 365 in your home lab without any feature limitations.

 
LVL 104

Assisted Solution

by:Sembee
Sembee earned 500 total points
ID: 18893389
I cannot believe that the ISP is expecting this to be a public facing port. As Lee has stated above - the entire SMTP system is based on the port 25. Like http is port 80, https is 443 and POP3 is 110.
This sounds like either a massive cock up by the ISP or someone has taken the private port (for client to ISP communication) and is treating it as the public facing port.

Simon.
0
 
LVL 1

Author Comment

by:alchik
ID: 18897854
I agree with you Sembee.  I've emailed their ISP support group directly (funny, their mail server works just fine...) to see if I can get an answer.  The client has tried to get an answer from them but the ISP claims it's everyone else's fault.  It's bizarre but seems it's not an isolated incident.  Dyndns.com offers MailHop to get around such things.  Odd....
0
 
LVL 104

Expert Comment

by:Sembee
ID: 18897917
The service that dyndns.com is offering is a private service. You send your email to them and then they send it on to the internet using the conventional ports. I suspect this is a similar service.

Simon.
0

Featured Post

Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.

Question has a verified solution.

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

The new Gmail Phishing Scam going around is surprising even the savviest of users with its sophisticated techniques.
New style of hardware planning for Microsoft Exchange server.
Nobody understands Phishing better than an anti-spam company. That’s why we are providing Phishing Awareness Training to our customers. According to a report by Verizon, only 3% of targeted users report malicious emails to management. With compan…
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an antispam), the admini…
Suggested Courses

765 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