DHCP Server Not Servicing anymore?! 1

[Trollotat]

Hi Guys,

first of all, I'm sorry if this issue is already answered too, I'm just a bit puzzled I guess...

Allow me to introduce myself, my name is Chris and I'm more or less a (Unix) System Administrator. My knowledge is frankly outdated as I didn't work in this domain for the last 5 years (sigh!). Even more, I'm used to Unix Systems (Solaris 6 and 7, and AIX 4.3 (ahem)) but Windows Networks, and specifically Active Directory, I'm clueless...

Now, my question isn't about Active Directory especially but about DHCP...

the setup is quite simple: PDC and SDC both run Win 2003 Server Standard Edition. They both are DHCP Server (I really don't know if it's a good idea or not... )

so far, all goes well... but yesterday, workstation has been upgraded (hardware-like) but the client cannot connect through DHCP...

when I put static IP, all goes fine, but when I try to go by DHCP, the client does not see the server...

I checked said server for clues... no problems on that side...

Event Viewer says nothing about it (it rather says all is fine so I tend to believe it's the case...)

I ran out of ideas...

I'm quite novice in Windows Administration, and have only limited access even as a domain administrator...

Any ideas would be welcome as these servers are in production...

Setup is for a School Network and teachers (and students) cannot access newly made computers...

Please help ? )

Best Regards,

Christophe Kowarski

 

[lhuegele]

The first thing you should do is turn off one of your DHCP servers. You should only have one DHCP server authority on your network, if nothing else, to help minimize things while you try to track down the problem you're having.

When you have fixed IP information on your workstation, is the remaining DHCP pingable? If you can't reach the DHCP server by pinging it, then the problem might be network related or network setting related. Make sure the fixed IP information on the DHCP server itself is correct. Double check it as well - the subnet and gateway information must be accurate.

If you CAN reach the DHCP server by pinging it, then you may need to make that DHCP server authoratative for your domain. To do this, open the DHCP snap-in on the server itself. Then right-click on the server name in the left-hand pane. You should see an option to "authorize" or "unauthorize". If you see "authorize", click it.

Good luck,

 

[GlenJohnson]

You can also go to the client, and do ipconfig /release, then ipconfig /renew to make sure the client has a good ip. lh is correct, you never want more than one dhcp server giving out ip's. The only time this would work is if you had 2 separate domains.

Glen A. Johnson
Johnson Computer Consulting

http://www.fred08.com/index.aspx

 

[cajuntank]

I too work at a school and normally you would only use one DHCP server that could serve for several VLAN'd subnets; however, don't totally discount the idea of having a second DHCP server for the sole purposes of a backup once you have a understanding of the Microsoft world. Microsoft goes through several design scenarios, one being the 80/20 scenario where you have one dhcp server handing out 80% of your subnet range and the other server handing out the remaining 20% on another server across on another subnet. Each server has exclusions setup for the other's ranges that are handed out. This way the first server queried will be the one handing out the majority of the addresses unless it fails and then the server handing out the 20% will be used. The downside to this is if the 80% server is down for too long, the leases would expire and the 20% server will not have enough addresses to possibly handout.

There are other Microsoft scenarios including a 50/50 failover and even a 100/100 failover approach (though this one involves using a larger subnet like a partial or entire class B range).

 

[GlenJohnson]

cajuntank is correct about the 80/20 rule. Check out my faq950-4927
On how it works. Good luck.

Glen A. Johnson
Johnson Computer Consulting

http://www.fred08.com/index.aspx