DHCP user class options for custom leases

phoeneous

How would one go about using the user class options to hand out a 4 hour lease for laptop users and a 1 hour lease for desktop users? I see that lease is option 51 but how does it differentiate the devices?

dynamik

I believe you need to run ipconfig /setclassid on the client devices.

Devilsbane

I know of organizations that do this, but I have a hard time believing that they run a command on every laptop.

Devilsbane

Unless you stick all of your laptops in an ou and configure a group policy for it that runs a login script to do that?

Devilsbane

Is there a way to force clients to use the new options?

Lets say the DHCP server has the options configured to tell clients that the DNS server is located at 10.0.0.5 which works fine.

Well now I move my DNS server to 10.0.0.6, but all the clients still think it is at 5. The only way I know how to do this is to run an ipconfig /renew on the client, but to go around to dozens of clients could be quite time consuming. You could send out a company wide memo to run the command, but that is a lot to be asking our non technical users.

I'm just wondering if there is something you can do on the DHCP server to update the information with all of the clients that are leasing addresses.

phoeneous

Devilsbane wrote: »

Is there a way to force clients to use the new options?

Lets say the DHCP server has the options configured to tell clients that the DNS server is located at 10.0.0.5 which works fine.

Well now I move my DNS server to 10.0.0.6, but all the clients still think it is at 5. The only way I know how to do this is to run an ipconfig /renew on the client, but to go around to dozens of clients could be quite time consuming. You could send out a company wide memo to run the command, but that is a lot to be asking our non technical users.

I'm just wondering if there is something you can do on the DHCP server to update the information with all of the clients that are leasing addresses.

Good question.

On a side dhcp note, Ive read conflicting sources that if you do a manual backup of the dhcp database on one server you cannot restore that database to another server. But according to this book you can. Ill try it out tonight to confirm, at work right now.

Devilsbane

phoeneous wrote: »

On a side dhcp note, Ive read conflicting sources that if you do a manual backup of the dhcp database on one server you cannot restore that database to another server. But according to this book you can. Ill try it out tonight to confirm, at work right now.

I thought you could, but you have to restore the registry settings on the new dhcp server as well and then reconcile the database.

Devilsbane

Devilsbane wrote: »

Is there a way to force clients to use the new options?

Found a similar post on another forum. Most people said it isn't possible.

One person suggested selecting the leases on the dhcp console and deleting them. I don't think this will do it because deleting a lease on the dhcp server doesn't notify the client. It is my understanding that the client will continue to use its lease until it tries for renewal. I think this will just make a mess when the dhcp tries to hand out those addresses again.

Another poster suggested using a GPO with a login script. Which should work as long as the users aren't logged in already. He also then went on to suggest scheduling a task to run the script. I'm not sure how to create a scheduled task that will be done on every workstation. I'll have to look into it.

Devilsbane

Didn't turn anything up with that scheduled task. Another thing I thought it would be useful for would be to force a gpupdate on all workstations. Does anyone know how to do it?

dynamik

Group policy updates every 90 minutes with an offset of 30 minutes. You can change that interval to something less if you need.

You can also use psexec to execute gpupdate on remote computers: How to Force Remote Group Policy Processing

You could probably use it for the other tasks you're asking about if the logon/off scripts don't work for you.