New DHCP server, PC's keep losing connectivity
Posted on 2011-05-12
My company has 3 VLANs, Regular, Production, and Wireless. Previously, our DHCP has been handled by our Sonicwall Pro 4100 firewall. We want to move DHCP over to a regular server in anticipation of changing our domain.
I have a server running as a domain controller for the new domain, but no nodes have been assigned to it yet. It has, however, been set up to serve as a DHCP server.
After some trial-and-error, the new DHCP server seems to be working fine except for a problem on the Production subnet. Note that the DHCP server is giving out 8-hour leases.
The Production subnet is set up so that if a node is plugged in on a Production port, the DHCP server only assigns an IP based on a MAC Reservation. So it's basically MAC filtering. Also, devices on the Production subnet are limited at the firewall to two shares on the Normal subnet and one site on the Internet.
Currently, if I switch over to the new DHCP, I can go to a particular machine and do an ipconfig /release and /renew to have it go ahead and pull its IP from the new DHCP server. Everything goes fine for a while, but eventually, it loses connectivity. And then it comes back. And then a couple hours later, it goes away again. So then I turn off the new DHCP and turn the old back on, and it still happens a little later. Eventually they have to keep shutting down and restarting to regain connectivity for a while (as I left it tonight).
In a previous experience, when the first device began having problems, I did a release/renew on another machine and it started having the same problems, so I don't think it's the particular machine.