Exchange 2010 and sending emails through third party smtp server?

Question

SMTP

The following task arose:
There is a mailbox on a third-party service (smtp \ pop3) for domain1.ru
There is Exchange 2010 in the organization for domain2.ru
The [email protected] must store mail in the exchange mailbox, but mail must go through the server third-party organization (both sending and receiving)
What are the implementation options?
PS
One of the ideas I have is forwarding emails from [email protected] to [email protected](exchange) to store emails in an Exchange mailbox. However, I have no idea how to implement sending letters from an Exchange mailbox through a third-party smtp server. Actually, this question was asked in the title, but there may well be more reasonable implementations.

Answer 1

I have Сentos(Postfix+Spamasassin+Amavis) as a relay for exchange 2013 mail filter and redirection
man1
man2
man3
other manuals in my head, in fact you need to configure the connectors: "Receive Connectors" and "Send Connectors" to work with relay