DHCP Lease Options

[quinla01]

Hi Guys, got a problem i was hoping someone could clear up for me.

I've recently migrated my DHCP service from an NT box to a 2003 box. I used the propper tools and everything seems to have gone ok.

The problem i have is that the lease duration on the NT box was configured to "never expire".

As you can imagine, over the years the scopes have become pretty messy and i'm sure that many of the lease records belong to machines on the network that no longer exist.

I've configured the 2003 leases to have an lease duration of 5 days ( i have a fair few mobiles users and have therefore decreased from the default 8 days).

Most the records on the new 2003 system are still set to "infinite".I was wondering what the best way to clear up the old records is. I didn't want to delete all the records since i fugure this could cause IP conflicts, am i right?

Any help would be much appreciated.

Thanks

Andy

 

[58sniper]

I think during the bootup, the workstation still tells the server it's going to use that address.

I'd find a machine that's nearby, find its lease in DHCP, delete it, then boot the machine and see what happens. I think you'll be safe.

Pat Richard, MCSE(2) MCSA:Messaging, CNA(2)

 

[markdmac]

Pat is correct.

Deleting the lease will not hurt anything. The system will simply request to renew the existing lease.

Even with a one day lease, most machines will keep the same IP address forever due to the renewal policy.

Renewal works like this. Say you have an 8 day lease. At each reboot the system will request to renew the lease. if the PC stays on it will ask to renew at day 4. If no response is received it waits another 2 days, then 1 day, then 12 hours, 6 hours etc. The time just keeps getting cut in half until the lease either renews or expires.

Inform all of your users to log off one evening and then delete all client leases. The PCs will automatically check back in and only renew those leases that are actually being used, so you will free up the leases from dead machines.

I hope you find this post helpful.

Regards,

Mark

 

[quinla01]

Cheers guy, i will give it a go on a scope an let you know how i get on. I'll backup the database first just in case.

Thanks for you help

Andy