Thread: The Port Forwarding

Hi,all

I have been surprising about this for a moment and not able to obtain answer. Why do some services, like Apache Web Server, Databases and such need you to forward the ports on home router, but other applications, such as AOL Instant Messenger do not require ports forwarded?

Hi,

If the connection is set up by outside client, you have to forward the port. This is because incoming request is a mystery to router; it does not know which machine to send the packet to.

OTOH, for stuff like Messenger, it is the client and connects to the AOL host, which runs the remote connections, so no port forwarding is necessary

Hello,

If you actually want to dive deeper then read up on OSI seven layer models, particularly the transport and sessions layers with some importance on temporary ports.