All, I also have a cable modem and a front end ISA server, the server has to pick up DHCP addresses for the external interface from the ISP and the lease time is 1 day and this works fine with the DHCP client packet filter enabled, on occasion however, the lease time returned is 1 hour and the DHCP server seems to reject any attempt to renew the lease. Once the lesae has expired the server assigns itself an APIPA address (169.254.x.x) but will not pick up another address from the DHCP server unless the firewall service is stopped within ISA, I have also tried disabling the APIPA so the address reverts to 0.0.0.0 but it is still unable to pich up a new DHCP lease while the ISA firewall is running. This could be a problem with the ISA software itself but if I can't find a solution I will have to consider scrapping the cable modem and going with ADSL, Demon Internet offer a static IP address as part of their ADSL package which will make all of the problems go away. Robert