9X machines hang – connectivity issue

I’m using W2K DHCP to lease ip’s to 9x clients. Clients recieve lease ok but intermittently hang. No connectivity – check TCP with ipconfig /all all setting look good – then use ipconfig release – renew and everything starts working. Problem may occur again within a few minutes or longer not consistent with any machine. A machine that fails may work for days with no problem.
Lease is for 8 days.

TIA