Solved

Client connecting to wrong DHCP Server

Posted on 2010-11-08
27
1,290 Views
Last Modified: 2012-06-27
I have about 5 users who use laptops running windows xp on our network. Some of them (not all) get connected to the wrong DHCP server. When i do an ipconfig/all on these clients, i see the IP address of the DHCP server they are connected to is that of a Windows Server 2008 server that i have running. The problem is that the server is not configured as a DHCP server.

Why would some client be connected to the correct DHCP server and some would not? Any thoughts on how i can fix this?

Thanks
0
Comment
Question by:jkpc21
  • 12
  • 7
  • 5
  • +2
27 Comments
 
LVL 7

Expert Comment

by:OxygenITSolutions
ID: 34087388
DHCP should be allowed/blocked through your network equipment.
Anyone can configure DHCP on a laptop and cause issues on a network.

If you allow only one DHCP server through your network, then you should eliminate this issue.
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34087480
How do i allow only one dhcp server on our network? The DHCP server they are connecting to is one of my server that is not configured as DHCP.

Thanks
0
 
LVL 17

Expert Comment

by:sweetfa2
ID: 34087499
if it is ansswering dhcp requests it is configured as such.  check the services for it.  it may also have dhcp-relay configured
0
 
LVL 27

Expert Comment

by:davorin
ID: 34087548
Maybe the DHCP server is not on that server, but you have in network another device with the same IP address and DHCP server enabled.
Have you tried to access that IP over web browser on the problematic PCs? Maybe this way you can find out what this device is.
0
 
LVL 15

Expert Comment

by:wantabe2
ID: 34088477
That server is configured as a dhcp server. Click start-run type in services.msc and look for the dhcp service and stop it. Then go into configure my server and remove the dhcp role
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34088839
Here is a screenshot of the server roles enabled on the server.

I also double checked all devices on the network and no other device is setup as a DHCP server and no other device is using the same ip address as the server.
Server-Roles.jpg
0
 
LVL 27

Expert Comment

by:davorin
ID: 34088874
"and no other device is using the same ip address as the server."
Can I ask you how have you checked this?
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34088902
I went through all internet enabled devices connected to our network.
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34088918
When i type the ip address from the problomatic machine, it takes me to a IIS7 welcome page. Now IIS is installed on the server with that ip address.
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34088923
It actually goes to the IIS7 welcome page when i type the ip from a working machine as well
0
 
LVL 27

Expert Comment

by:davorin
ID: 34088956
OK, thanks.
That is a little bit strange as you don't have DHCP server installed on that machine as still it is acting as DHCP server. I have proposed to try that, because some users are connecting equipment to the network and administrators are not informed about that.
Do you have some other "third party" software installed on that server that it is acting as DHCP server.
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34088979
Aside from the antivirus software, there is nothing else installed on the server.
0
 
LVL 7

Expert Comment

by:OxygenITSolutions
ID: 34088996
Is the DHCP relay on your router pointing to your server?
0
IT, Stop Being Called Into Every Meeting

Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

 
LVL 27

Expert Comment

by:davorin
ID: 34089008
Well, there is one test to be sure, but I think you can use it off working hours.
Connect only that server and a DHCP enabled client to a standalone switch and see what IP address it is getting the client. DHCP clients normally gets IP address from DHCP server who answers their request first.
What is IP address of that server? (192.168.0.1 or 192.168.1.1? )
0
 
LVL 7

Expert Comment

by:OxygenITSolutions
ID: 34089018
On that subject, what is the IP address you are getting? It may be a self assigned one.
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34089047
I just saw that the default gateway is also incorrect on the client machine. So not only is the dhcp ip address pointing to my server, the default gateway also has the same IP address.

The ip address that the client is getting is correct, its the default gateway and dhcp server thats incorrect.
0
 
LVL 7

Expert Comment

by:OxygenITSolutions
ID: 34089066
Check the Gateway address. Type it into a browser and see if it asks you for a password and sometimes that reveals the source. Use http and https . If you recognise the gateway IP address, check that device.
0
 
LVL 27

Expert Comment

by:davorin
ID: 34089068
And that is what?
0
 
LVL 27

Expert Comment

by:davorin
ID: 34089100
I meant what IP address of DHCP server you get...
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34089125
The gateway address that it is giving me is that same as the dhcp address it is giving me. When i type them into the browser it takes me to an IIS7 welcome page.
0
 
LVL 27

Expert Comment

by:davorin
ID: 34089180
Try the suggestion at my comment ID: 34089008
0
 
LVL 15

Expert Comment

by:wantabe2
ID: 34089250
do you have RAS setup on a Win server somewhere on your LAN?
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34089301
No RAS server
0
 
LVL 7

Expert Comment

by:OxygenITSolutions
ID: 34089468
Can you go start run \\gatewayipaddress\c$ or a known share on the problem workstation and one on a correct workstation and confirm it is in fact the same server and not some other server with the same ip.
0
 
LVL 3

Author Comment

by:jkpc21
ID: 34089500
I think i may have figured it out. On one of the machines that was having the problem i restarted the wireless zero configuration service and once i did that the machine picked up the correct information and was able to go online without any problems. I'll have to wait until tomorrow to test the other machines.
0
 
LVL 3

Accepted Solution

by:
jkpc21 earned 0 total points
ID: 34096009
Just to give everyone an update. I was able to solve the problem on all clients by restarting the Wireless Zero Configuration service. Once restarted, the client was able to connect to the network and obtain all the correct information (i.e dhcp, gateway, ip address).

Thank you everyone for your help and suggestions.
0
 
LVL 3

Author Closing Comment

by:jkpc21
ID: 34130238
The solution to the problem was to restart the Wireless Zero Configuation services on the client machines.
0

Featured Post

Enabling OSINT in Activity Based Intelligence

Activity based intelligence (ABI) requires access to all available sources of data. Recorded Future allows analysts to observe structured data on the open, deep, and dark web.

Join & Write a Comment

Scenario:  You do full backups to a internal hard drive in either product (SBS or Server 2008).  All goes well for a very long time.  One day, backups begin to fail with a message that the disk is full.  Your disk contains many, many more backups th…
I was supporting a handful of Windows 2008 (non-R2) 2 node clusters with shared quorum disks. Some had SQL 2008 installed and some were just a vendor application that we supported. For the purposes of this article it doesn’t really matter which so w…
This tutorial will walk an individual through locating and launching the BEUtility application and how to execute it on the appropriate database. Log onto the server running the Backup Exec database. In a larger environment, this would generally be …
This tutorial will give a short introduction and overview of Backup Exec 2012 and how to navigate and perform basic functions. Click on the Backup Exec button in the upper left corner. From here, are global settings for the application such as conne…

746 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now