DHCP address releases

[ade]

Hi all,

We have 3 sites with a dhcp server on each site each with a redundant scope
for the other 2 sites. An IP helper address is configured in the switches
so that if the local dhcp server dies, the request is routed to the quickest
reply from another sites dhcp server. Our addresses are not being released,
when a laptop user goes to another site, the ip address from the original
site is still bound to the adapter, thus having a wrong IP adress. Is this
by design? Or is there a way to force the client to release the dhcp ip
address at shutdown?

 

[Guest]

I would create a script with the command ipconfig/release to execute during
logoff or shutdown. I believe it can be done using a GPO I might be wrong
tho...

 

[Tanu Mutreja [MSFT]]

If DHCP Client has valid lease for an IP address and the client is able to
ping DefaultGateway while booting-up, system will continue to use same IP
address till the lease is valid. As suggested, "ipconfig relesae/renew" can
be the only way out.

hth
-Tanu Mutreja [MSFT]

 

[Phillip Windell]

We have 3 sites with a dhcp server on each site each with a redundant scope
for the other 2 sites. An IP helper address is configured in the switches
so that if the local dhcp server dies, the request is routed to the quickest
reply from another sites dhcp server. Our addresses are not being released,
when a laptop user goes to another site, the ip address from the original
site is still bound to the adapter, thus having a wrong IP adress. Is this
by design? Or is there a way to force the client to release the dhcp ip
address at shutdown?

It is usually because they didn't really hut them down but only "hybernated"
them.

Futher problems will occur if you use Superscopes where they don't belong.
Legitimate use of Superscopes is rare. They are almost always never needed.

You DHCP design sounds fishy too. Switches don't do what you say yours is
doing,...routers do that, and they are called "helper addresses" or "DHCP
relays",...and they always do it by which one answers first, whether a
server is down or not.

 

[Guest]

Run a script/.bat file that executes the ipconfig/renew command during the
login process. I believe this can be done using a GPO.

 

[ade]

Phillip, your correct, I should have said router.

The IP helper works fine is the local server is down, it's the non-releasing
of addresses that bugs me, I read the tech note/explanation and really am
just looking for ideas and suggestions on how you guys deal with the issue.

Thanks for everyones help

 

[Phillip Windell]

Phillip, your correct, I should have said router.

Ok,.. sorry,.. no problem.

The IP helper works fine is the local server is down, it's the non-releasing
of addresses that bugs me, I read the tech note/explanation and really am
just looking for ideas and suggestions on how you guys deal with the

issue.

I have never had it happen. But It usually happens because the user did not
really power off the machine, they only put it in Hybernation and "thought"
they shut it down.

 

[ade]

Hi Phillip,

I've come across that one aswell. Just find it wierd that DHCP operates
like it does, not very friendly use for roaming users.

Thanks for your help anyhow.