Change port Exchange SMTP uses

Recent problem posted on the NG: 

We do not have a static IP. Our ISP requires that we forward mail to their SMTP server on port 1025 instead of port 25. When I look at the SmallBusiness SMTP connector there does not appear to be a choice for the SMTP port. Is there a way to specify port 1025 for just their smarthost?

The answer (provided by Henry Craven) was:

1. Shut down the Exchange services
2. Go to: %systemroot%\system32\drivers\etc\services file
3. Edit the contents for the smtp service to specify another port number
smtp   25/tcp  mail          #……

and change it to:
smtp   1025 /tcp mail      #…..

4. save the file then restart the Exchange services.

Thanks, Henry!

3 thoughts on “Change port Exchange SMTP uses

  1. Hi,

    You’re making it difficult for yourself and also difficult for someone to support at a later date.

    Open ESM, go to Servers->[SERVER]->Protocols->SMTP

    Right click on the SMTP virtual Server in there, hit properties.

    Click Delivery -> Outbound Connections, and set whatever port you want in there.


  2. Hi

    what if I’ve done both, and in the ESM GUI I see port 26, also in sevices file, still if I try

    telnet 26

    it does work, but on port 25 my exchange answers?

    Any good idea?



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