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

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