forcing dhcp renew across network

[russdev]

ok changed ip setup numbering to be in align with lea recommendations..

 

Anyway some clients till got old ip number as they have not renew yet..

 

Is there anyway of forcing all clients on network to renew themselves

 

Russ

[Geoff]

reboot them or try these commands:

 

ipconfig /release
ipconfig /renew

[MkII]

Force the DHCP lease renewal do you mean?

[russdev]

yes

 

rebooted w/s them seems like they have kept old number still

 

but dont fancy going around 100 odds computers and renew them all by hand

[Ric_]

If you unplug the network cable and then plug it in again I think that they renew - I seem to remember doing this at some point.

[Dos_Box]

You could just shout down all the clients and flush the DHCP and DNS cache too.

[russdev]

so how do you do that have brain dead moment

 

russ

[ChrisH]

I assume he means execute the command on all computers using something like psexec and text files of your computer names.

[Ric_]

I think Dos_Box meant shut down all the clients and make sure that all the leases have been deleted from the DHCP server.

[russdev]

did that first time around i think problem is it was left on default lease of 60 days so not going to look for new one for 60 days.

 

Russ

[SpuffMonkey]

Can you not just power down, delete their lease entries on the DHCP server and reboot?

[Dos_Box]

I did mean shut down. It must have been something Fraudian going on there.

[russdev]

yer tried pwoering down and deleting but still gets old ips even through they have been taken out of range

 

only thing i can think is was set to keep ip for 60 days so not looking to renew it yet hence want to try and renew it gloabbly

 

cant use psexec as when release losses net connection

 

only

[Dos_Box]

Use the /renew switch would be your best bet, but if you have 2 DNS servers and you don't deleate the records from both then you may have problems with ghost IPs' popping up.

[GrumbleDook]

Pick up a copy of ADSI scripting for Windows 2000 ... there is a WMI call in there for doing this remotely. Unfortunately my spare copy is at work (my real copy is with one of the other guys!)

[tarquel]

I did this - if we are on about changing the ip range on a network - and although all the machines had changed their ip, they were still looking for the old DNS IP [as the server had changed IP too naturally].

 

I've had to wipe them all - as i've said in another topic [no time to link right now]

 

Just so ya know - hope u dont have that problem lol

 

Regards

N.

[MkII]

In the DHCP Server Options > advanced tab, microsoft options > there's an option to release DHCP on shutdown

[russdev]

in end what did was download psexec and create a batch with

 

ipconfig /reelease

ipconfig /renew

in it caled it test.cmd

 

then in second batch file put called redo.cmd added: -

 

rem @echo off

cls

net use s: \\%1\c$

if exist s:\test.cmd goto endfile

copy test.cmd s:\ /Y

net use s: /delete

 

psexec \\%1 c:\test.cmd

 

:endfile

net use s: /delete

 

 

once that was got list of w/s in excel in column b and then word redo in column a

 

then in c col did formula =A2&B2&C2 copies all way down then copies col c into notepad saved as do.cmd

 

ran do.cmd and it is just working through the list

 

Russ

[tarquel]

nice one russ

 

nice 'n' simple script

 

Nath

[Westbrooke]

Sounds like fun!

 

First, make sure you reduce the DHCP lease time on your new setup - 3 days is more usual to jelp avoid problems.

 

Exact behaviour of DHCP depends on the verisons of client and server (although it is supposed to be a standard)

 

Basically, if I remember correctly, clients will try to get a renewal after half the lease time has expired. If they don't get one, they will carry on with the old IP until the leae runs out.

 

However on boot up they should try and check their lease with the DHCP server they got it from, and hope for an acknowledgement (ACK).

 

Unless you plan on waiting 30 days (I suspect not) you need to get this boot up process to deliver a negative acknowledgement (NACK)

 

To do this you first need to make sure that your DHCP server knows that these addresses are no longer valid. By the sound of it you have done that.

 

The second part is to make sure that machines booting up with the old IP address can still access the DHCP server. If they can't, they will just carry on withthe old IP address.

 

It sounds as if part of the IP address changes you have made as removed the valid network route from PCs with old numbers to the DHCP server with an old number. Have you change the whole IP subnet and re addressed the DHCP server?

 

If that is the case, you have 2 options.

1. run arund all the machines and renew manually :-)

2. Set the DHCP server up as dual homed - with two IP addresses (old and new) and set to cancel the old scope and issue addresses on the new scope. Then reboot PCs and you are away. Once they are all done, don't forget to tidy up the DHCP server.

 

Hope that helps.