Solved

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

Posted on 2007-04-11
8
235 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
  • 3
  • 2
8 Comments
 
LVL 31

Accepted Solution

by:
LeeDerbyshire earned 125 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
PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

 
LVL 104

Assisted Solution

by:Sembee
Sembee earned 125 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

Best Practices: Disaster Recovery Testing

Besides backup, any IT division should have a disaster recovery plan. You will find a few tips below relating to the development of such a plan and to what issues one should pay special attention in the course of backup planning.

Question has a verified solution.

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

This process describes the steps required to Import and Export data from and to .pst files using Exchange 2010. We can use these steps to export data from a user to a .pst file, import data back to the same or a different user, or even import data t…
This is my first article on Expert Exchange on the Manual Method of Exporting Office 365 Mailboxes to PST format by using the eDiscovery mechanism of Office. Hope you will enjoy the article.
In this Experts Exchange video Micro Tutorial, I'm going to show how small business owners who use Google Apps can save money by setting up what is called a catch-all email address in their Gmail accounts. By using the catch-all feature, small busin…
Internet Business Fax to Email Made Easy - With eFax Corporate (http://www.enterprise.efax.com), you'll receive a dedicated online fax number, which is used the same way as a typical analog fax number. You'll receive secure faxes in your email, fr…

895 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

13 Experts available now in Live!

Get 1:1 Help Now