Hi, I am having a strange thing occur with many of my workstations. We use DHCP and all Windows 2000 and XP machines are ok with this of course, but for some reason some Windows 95/98 PCs are grabbing a valid (192.168.**) address but instead of having 255.255.255.0 in the subnet it is specifying 255.0.0.0. This is of course also meaning the PC is off the not contactable on the network. Has anyone any ideas why this may be happening? We use VLANing structures within our network. After I do a release/renew in Ip config an ip has obtained and the subnet mask goes back to 255.255.255.0. Any help would be greatly appreciated! Thanks, Steve

Sounds like a Rogue DHCP server to me... Please help survivors of Hurricane Katrina...err...Rita. Starting to lose track... www.redcross.org

I would leave your 2000/XP machines on DHCP and set your 95/98 machines to a static IP address and make the nessecary arrangements in your DHCP Server. --Benjamin Johnson Central Help Desk

Hi, Thanks for your feedback! We cant really use fixed addresses and we have hundreds of Windows 95/98 PCs unfortunately! Any further suggestions anyone? I suppose it may be looking like a PC issue so not much we can do centrally? Thanks, Steve

Check your network for a Rogue DHCP server. How else would those clients get a DHCP lease with so much correct, but one value that isn't? Shows me DHCP is working on the client. Obviously, your server is working right because your other computers are getting the right addresses, and these get the right address when you try again. Please help survivors of Hurricane Katrina...err...Rita. Starting to lose track... www.redcross.org

The DHCP server that the PCs obtain an incorrect subnet mask from is exactly ther same DHCP server that all other ok machines use. This led me to think there was nothing wrong witht he DHCP server? I have checked it and it all looks ok. VLANing and Cisco switches couldnt come into this could it? We have just implenented the VLANs and this is when it has started occuring. However before everything was on one VLAN on a different subnet than the new one. Thanks

DHCP uses broadcast requests for IP leases. If the DHCP server is not on the same VLAN as the clients, that's a problem. You could use a DHCP relay agent or setup another DHCP server on that VLAN. Please help survivors of Hurricane Katrina...err...Rita. Starting to lose track... www.redcross.org