Running ROM on ICS network

I'm trying to run my server via ICS (internet connection sharing) on windows xp

AT&T Broadband ---> Directly connected machine ----> Me (w/ server) I myself can connect to to it but anytime I try to have a friend connect to my computer's IP (192.x.x.x) he's refused.

Now, I've tried having him connect via the IP of the net connection (the one AT&T assigns to it) and it still won't work.

I've narrowed it down to one of two things... either the ICS is preventing it or AT&T has some sort of firewall up that stops it (its running on port 4000 atm)

any ideas?

There is a discussion about ICS on this forum, see the post ICS Issues?.

The next issue is that the addresses 192.x.x.x are private addresses - they cannot be advertised on the Internet as they are for internal networks. In the case of ICS (and other similar software) the external IP address (of which you will have one) is changed "on the fly" to the internal addresses, thus sharing the Internet connection over multiple PCs.

If the PC running the server is not the one which is actually doing the ICS switching then it will not handle incoming connections, because it doesn't know which PC to forward a request to establish a connection (eg. to port 4000) to.

This can be worked around with some software by a technique called "port forwarding". Basically you configure the switching software to say "if a connection for port 4000 arrives, send it to internal address x.x.x.x (the 192.x.x.x address).

I haven't used ICS but I would look at its configuration to see if it supports such a thing.

Regrettably Nick, it didn't work out :( I set up ICS to forward the 4000 port requests onto my computer and then tried to connecto to the IP of the net connection via mushclient... still didn't work.. :-(. I miss being in control of the connection (it used to be set up that I was the server for ir, now my dad is... and he won't let me run the thing on his computer

The theory is right, maybe something needs tweaking. :)

Make sure you direct port 4000 TCP not UDP. Also, try connecting from outside (eg. get a friend to do it), it mightn't work if you do it from inside the local network.

Failing that try to get a packet sniffer to report what is happening, and look at the ICS logs.

when you use ICS on XP, the internal network cannot use the external ip for a server thats on the lan (wierd i know)

your friends can use your external ip (at&t assigned) but you need to use the internal ip (192.whatever) to connect.

as long as xp's port forward is setup properly, this will work - i do it myself ;)