Internet connection sharing problem

I have a peer to peer network with the internet
connection (ISDN) on a machine running XP professional
and the ICS Client running Windows 98 version 2. All is
well with the network except the ICS Client appears to be
dialling the internet at random intervals and does not
run either a browser nor does it hang-up the line. The
Host computer does not do this.

How do I stop this happening? I have disabled the ability
to dial on-demand as a short term workaround but this is
not too satisfactory!