Using PORT 26 for as SMTP with Spam Filter as relay host

Question

Hello,

I am fairly new to AWS and a slowly trying to gather knowledge about what is right and wrong to do.

I have a question about SMTP.

Because PORT 25 is blocked per default I noticed that we could use PORT 26 for SMTP instead.

We run a HCL Domino Server on-top of Windows and use a Spam Filter as relay host so we have some measurements in place.

Would that be okay to do or would it be looked at as bad practice?

Thanks in advance.

Best regards
Kristian

Accepted Answer

AWS blocks outbound traffic on port 25 (SMTP) of all EC2 instances and Lambda functions by default. Using port 26 SMTP is one way to work around this problem, but If you want to send outbound traffic on port 25, you can request for this restriction to be removed by AWS.

Using PORT 26 for as SMTP with Spam Filter as relay host

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