DHCP Release and renew rights

[wimvanherp]

This year we have to change the whole ip-range on our network. As we work with DHCP i would like to do an automatic dhcp renew as soon as the ip-range has changed. Does someone know if there is a good program doing this. I had already found a service that performed this (without rebooting !) but it locks the pc after some days. So technically it must be possible . Wim Vanherp
Wim.Vanherp@belgacom.net

 

[bradje]

you could have a little batch file in the runonce directory to do it.
eg

ipconfig /release
ipconfig /renew

But I thought if you reboot the machine it should check anyhow??

JB

 

[alfie1noakes]

If using DHCP, your client machine will only renew its IP address automatically, if you have a lease specified for your IP addresses in the DHCP setup. Otherwise once an IP address is assigned, your client machines will always have this address and it won't get released. We typically have IP addresses to renew every 3 days.

You can also use ipconfig from the command prompt or on Win 9* you can use winipcfg and this will allow you to manually renew client IP addresses with a nice GUI.

 

[wimvanherp]

ipconfig /release and ipconfig/renew only work if you have
administrator rights, so it does not work if you work from a login script for normal users Wim Vanherp
Wim.Vanherp@belgacom.net

 

[Whoheard]

The NT.40 and W95 WS will always check with the DHCP server during boot up, even if it has time left on its lease. This insures that the information is always current. If a change is made to the scope, i.e. new gateway or DNS addition, the WS will get those changes.

Two things are likely to happen when you change things. 1.) you must change the router's ip on the segment--gateway. This will cause the users to not get a response from the DHCP server during boot process because the gateway no longer exists; and the WS will continue using the old IP. 2.) The router must have both the new and old address on it and the scope must be deactivated. The router will forward the DHCP Request and get a DHCP NACK back from the server. As long as the old scope is not active, it will not get any information and the WS will have to broadcast for a new address.

So a simple reboot will take care of the DHCP process as long as the other parameters are correct.

Hope this helps.

Bob

 

[bradje]

Thanks Bob
Thought this was the case, but wasn't quite sure
JB

 

[wimvanherp]

This is new for me, I'll try it out.

Thanks a lot anyway Wim Vanherp
Wim.Vanherp@belgacom.net