Port/Protocol forwarding

Neorio · 04-12-2004, 02:04 AM

Can someone explain port/protocol NAT forwarding to me? I don't see how or why it's used.

I understand IP Masquerading and such, but I don't get port/protocol forwarding.

maxut · 04-12-2004, 02:37 AM

DNAT (port forward) is used to publish server behind linux firewall.
go to www.netfilter.org and read the docs for detailed info.

ugge · 04-12-2004, 02:54 AM

Because how the NAT functions you can't reach a server behind the NAT.
The only IP addresses that are known to the outside world is the official IP of the server.
To get to a server behind the NAT you would have to forward the request using port forwarding.

So when a request or packet comes to the server requesting a particular service/port the router changes destination IP and port to a local computer behind the NAT.

Neorio · 04-12-2004, 03:38 AM

Thanks I get it now.

I've always wondered how my router worked using two PCs and both of the IPs stuck in the 192.168.1.0 range.

michaelk · 04-12-2004, 11:35 AM

Your PC's shouldn't have the same IP address i.e the last digit. 192.168.1.xxx will be different.