How to set up 2 mail servers with one external IP based on Cisco Router 2821?

Question

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Good afternoon. Help with setting up Cisco 2821 for 2 MS Exchange mail servers. Those. there are two mail servers with IP addresses 172.16.0.200/29 and 172.16.10.200/29 I would like both servers to be available through 1 external static IP for different organizations. As far as I know, in theory it can be done, but how to configure based on Cisco.

Answer 1

Or, as you have already been suggested:
* a separate server, something like Postfix, which will work as a mail router within the network.
or
* you simply send all mail to one Exchange Server, and implement External Relay on it to another server. Those. it will accept mail for everyone and stupidly forward to another hole on port 25.
More about External/Internal relay here