Renewing DHCP lease from outage

[thejackal85]

We have a multitude of servers in our environment that are all DHCP, but in our area, our power situation is very unstable. The power will go out and knock one of our switches offline. However, the servers will stay on.

When that switch goes offline and I bring it back up, not all of the servers will get the correct lease and I will have to reboot them or manually hook up a monitor and do a refresh. My question is does anyone know of a service/program that can kick in on those servers when this happens that can do a release/renew when it sees that the server has a 169 address?

Before any of you answer, I wanted to address a few things. We can't put them as static, because we need roles to go from one server to the other; so setting them as static would be a headache. We are in the process of moving power around and will eventually get our switches on our APC unit; so "plugging the switches into an APC to avoid an outage" is in the works. But we still get bigger outages that will knock out everything that would cause this anyway.

 

[bill001g]

It actually asks for a IP mulitple times before it gives up. Someone may remember where but it is possible to make changes in the registry to make this timeout longer.

The main time I have seen this happening was on switches that ran the older type of spanning tree. The ports would electrically be up but pass no data for a minute or so while the spanning tree ran. You want to be sure the ports going toward a server are set to be "edge" ports which causes spanning to not look for other switches on that port.

In general the default timeout should cause no issues. If the switches are advaned enough maybe you could capture data and see if it is the server that is not sending DHCP requests or the DHCP server not offering a IP.

 

[thejackal85]

Time timeout wouldn't make a difference, we have left servers in this state over the weekend to be handled on Monday and they still had the wrong lease.

The switch isn't the issue, it's the ethernet ports on the servers. I have seen this in other situations as they have gone bad, you need to release/renew or refresh the network settings every now and again. But my whole idea is I'm trying to avoid a reboot if the only thing wrong is the DHCP lease.

 

[unksol]

I'm sure there's better ways to handle this and they really should be static. But it would be very simple to run a batch file with a 1 minute loop and ipconfig /renew when a ping to the router fails.