Intermediate SMTP server?

Question

Mail server

Due to the fact that I can only raise external POP3 and IMAP, and SMTP - only for local mail, I need an additional server. Where can I get a working smtp for free to work in this mode - if the outgoing message has a recipient address on the local network, then the SMTP server delivers it to the right box, and if the outgoing message has a recipient address on the Internet, then the SMTP server redirects the letter to another smtp server , which delivers the letter to the right place?!
Tell me, please, where can I get such a server and how to set everything up!

Answer 1

spammers
from your domain without DKIM SPF will still normally not send to no,
use Yandex for the domain and operate with it