Contstant dial out with ICS

I have two PCs running XP Pro (SP1). One is an ICS gateway, the other a client. Whenever I turn on the client machine it causes the gateway to start dialing my isp. It continues to do this every 30 seconds or so, even if I cancel the dial-out, making the gateway PC almost unusable. I cannot find what might cause this. All I know is that it is generic host processes services that starts the dial up. I know this because when I deny it access to the local network (using Zonealarm) then dial ups do not happen. However, that stops me using the network at all. Anyone know which GHP service will cause this dial out?
I have just upgraded the client from Win98, and this never dialed out.

 

I'm guessing but by chance in Tools > Internet Options > Connections > do you have 'always dial my default connection' enabled?

 

I have tried both with and without this setting. The gateway dials out regardless.

 

I think I would be inclined to download and run Hijack This on at least the client machine.

http://www.majorgeeks.com/download3155.html

 

I've solved the dial out, if not the problem. On the advanced tab of the dial up connection proerties, the setting "Establish a dialup connection whenever a computer on my network attempts to access the internet" was on. I set it off and now no dial up.
Of course that means I have to connect on the gateway before the client can use the internet, but I'm OK with that.
I still didn't find what was dialing though. I don't thinks its malware or a virus though because I only just installed Win XP. And I got NAV2003 and Zone Alarm up before any internet access was attempted.

 

I think that is normal, the gateway has to have a connection to the internet before anything that is ICS can.

More than likely, the machine had a regular dial up connection at some point that was never deleted?