Hello,

i need to send couple of e-mails weekly via an SMTP server of an free mail provider.

smtp.provider.com
port: 465

Apparently they dislike my IPs.

But i have a Linux CentOS server with a domain test.com hosted on it which has different (probably not blocked) IP.

I got an idea i may setup some redirect/proxy on my server so i face that smtp server via non blocked IP. And use this SMTP:

smtp.test.com
port: ?

and it will then redirect the request/data to the smtp.provider.com and to the correct port also. Do you have idea on how to do that?

Configure your smtp.test.com as a server that accepts traffic from your "disliked" IPs and then use smtp.provider.com as a "smart relay" / "relay host" on smtp.test.com

As you give no information about what your using as your MTAs that's about as specific as it can get.