DHCP/DNS not passing through switch.

[Gustave]

Great Mondays...
So last Friday we had some rough weather and possible power outages. This morning I come in one of our subnets(call it Y) is not getting ip addresses from our W2k3 DHCP/dns server. If I hop on the subnet(X) with the server it receives an IP fine and all is good. I can static set the ip and dns servers while on subnet (Y) and everything works fine. We have a managed Cisco switch doing routes for subnet (Y) and subnet (X). Our mpls subnets are working fine.

I am assuming that an IP helper was adding to (Y) subnet interface on the switch but was not saved to flash. When the power surged it rebooted and lost the settings. I can't be 100% that the IP helper was on there but I'm not sure what else would cause the problem.

Any help?

[Ratatapa]

can you plug a PC directly on the server without the switch see if it hands out the ip adresses?

If yes I think your switch block DHCP relays

[Gustave]

The subnet with the server is assigning IP's just fine.

My switch has 3 interfaces configured.
1/0/1 = firewall subnet
1/0/2 = workstation
1/0/3 = server

Nothing on 1/0/2 is receiving IP addresses from DHCP, which is odd because last week everything was working fine. I'm 99% sure we had a power outage last Friday night, which leads me to believe settings where not saved on the switch. Lovely Monday morning surprise. All of our switches/routers/modems are on UPS units with a generator backup. There should not have been a lose of power to the switches unless the ups unit failed. Really hard trying to figure out wtf went wrong. I never received an email saying power lose / rise in temp / or generator kicked on. Weird.

Not sure if this matters but normally if I have a machine that doesn't get an ip i can set it static without putting in dns server but now I have to set the dns servers too for them to get internet access.

[xerodok]

It's normal for your settings to get cleared if there was some kind of surge, however, if you are on a UPS, there is no reason for you to lose any configurations.

Are you sure the managed switch (Y) is still referencing the scope setup on your 2k3 to receive the DNS/DHCP settings?

[Gustave]

Once everyone leaves today I'm going to add an ip helper for the (2) w2k3 servers. I think this will resolve the issue.

Is this what you are asking xero?

[xerodok]

Once everyone leaves today I'm going to add an ip helper for the (2) w2k3 servers. I think this will resolve the issue.

Is this what you are asking xero?

If your network was working just fine prior to something happening, this shouldn't be necessary. Have you revisited the configurations of your switch (Y) compared to others? I'm referencing particularly your DHCP setup on the 2k3 server; the pool might be there but your switch is not accessing it because it has not been reconfigured.