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

You can have one application listening on one port for one network interface. Therefore you could have:

1. httpd listening on remotely accessible interface, e.g. 192.168.1.1:80
2. another daemon listening on 127.0.0.1:80

Sample use case could be to use httpd as a load balancer or a proxy.