Hi everyone, this is my first time posting for help, hope someone will get
it.
I want to use an SMTP Relay, like the one for Microsoft Exchange. I'm
looking for some Free SMTP Relay, Now I'm trying to get it done with
postmarkapp.com, but I'm a little bit confused...

I Already have my own server and I'm using Port25 MTA to monitor my emails.
So how can I configure my MTA with the SMTP relay please?
Correct me if I'm wrong somewhere, I'm not really sure of what I just said
either, it's just what I undesrtood