Can two applications listen to the same port?

Question

Can two applications on the same machine bind to the same port and IP address? Taking it a step further, can one app listen to requests coming from a certain IP and the othe

Answer 1

If at least one of the remote IPs is already known, static and dedicated to talk only to one of your apps, you may use iptables rule (table nat, chain PREROUTING) to redirect incomming traffic from this address to "shared" local port to any other port where the appropriate application actually listen.