Host for Dedicated Box blocks Port 25, can I still email directly off the server using Port 26?

Mail Man asked:

I have a server that I want to send email off of directly. Host is blocking Port 25. They have told me to go to WHM -> Service manager -> exim on another port (Set to 26)

Is this actually a solution? Can I email off the box with this? I have never had to do this before on any other servers I have had. My software is not working so I am trying to determine if its because Port 26 is not really a solution OR do I have a problem elsewhere.

No 3rd party smtp solutions please. I need to mail directly off the box using php mail function -> exim

My answer:


Your hosting provider’s advice is completely useless.

Port 25 is the well-known port for receiving mail from other mail servers. If you want to deliver mail directly to a destination, that is what you use. Most such sites will not be attempting to receive mail on any other port, so attempting to deliver to port 26 will do nothing.

You basically have two options:

  • Deliver to a third party email service on port 587. This is perfectly compatible with PHP mail() when you configure the local mailer (exim) to do this. This is called using a smart host.
  • Have the hosting provider remove the block for you. If they will not do so, take your business elsewhere.

View the full question and answer on Server Fault.

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