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Some Clients not obtaining correct settings from DHCP

Posted on 2006-04-28
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Last Modified: 2011-09-20
I need some help.

I have a small network with about 30 clients, 4 servers and 1 DC.

The DC is running Windows Server 2003 with no service pack

The DC is also running DHCP, DNS, WINS and RRAS.

The other servers are a mixture of 2000, 2003 and 2003 R2 running Exchange, SQL, file servers

The clients are a mixture of desktop and PCs but are all running XP SP2 with latest updates from WSUS.

The IP range is 10.0.0.0/24

The DC and DHCP server is 10.0.0.1


My problem is that over the last two weeks 5 machines have not been obtaining valid TCP/IP settings from the DHCP server.


Below are 2 results of an IPCONFIG /ALL from one of the problem machines.

As you can see the DHCP s server is being set to 10.0.0.254 instead of 10.0.0.1 and the lease is for 30 mins

I posted the 2 results because as you can also see sometimes the default gateway is correct but sometimes it is missing, which is when I get notified of the problem because users can't browse the web.

Also notice the Connection-specific DNS Suffix is being set to localdomain when it should be mydomain.local

The weird thing is that if on the clients I do IPCONFIG /RELEASE and IPCONFIG /RENEW, they obtain the correct settings and work fine for the rest of the day until they start their machines up the next day.

The other weird thing is that it is only these 5 machines that are affected. Everyone else works fine.


Things I have tried
Restart DHCP service on DC - No affect
Cold boot the DC
Reset TCP/IP on clients using netsh int ip reset command
IPCONFIG /RELEASE on the client following by shutting down and starting. The next time the machine logged on it obtained the correct settings including a week long lease. However the next day it started up and had the same problem again.
Multiple combinations of IPCONFIG /RELEASE & RENEW's


Other things to note
The DC has had nothing installed and no config changes for ages. It was up for 14 months until I re-booted last night.
The problem machines are a mixture of different hardware. They are all going through different ports on 3 different switches.
10.0.0.254 does not exist on the network.
There are no other servers or devices that are acting as dhcp servers.


Any help would be greatly appreciated


Thanks,


Paul



RESULT 1
********
C:\>ipconfig /all

Windows IP Configuration

        Host Name . . . . . . . . . . . . : isl-desk01

        Primary Dns Suffix  . . . . . . . : mydomain.local

        Node Type . . . . . . . . . . . . : Hybrid

        IP Routing Enabled. . . . . . . . : No

        WINS Proxy Enabled. . . . . . . . : No

        DNS Suffix Search List. . . . . . : mydomain.local

                                            localdomain

Ethernet adapter Local Area Connection:

        Connection-specific DNS Suffix  . : localdomain

        Description . . . . . . . . . . . : Realtek RTL8139 Family PCI Fast Ethernet NIC

        Physical Address. . . . . . . . . : 00-20-ED-26-FD-9A

        Dhcp Enabled. . . . . . . . . . . : Yes

        Autoconfiguration Enabled . . . . : Yes

        IP Address. . . . . . . . . . . . : 10.0.0.134

        Subnet Mask . . . . . . . . . . . : 255.255.255.0

        Default Gateway . . . . . . . . . :

        DHCP Server . . . . . . . . . . . : 10.0.0.254

        DNS Servers . . . . . . . . . . . : 10.0.0.1

        Lease Obtained. . . . . . . . . . : 25 April 2006 09:05:22

        Lease Expires . . . . . . . . . . : 25 April 2006 09:35:22




RESULT 2
********
C:\>ipconfig /all

Windows IP Configuration

        Host Name . . . . . . . . . . . . : isl-desk01

        Primary Dns Suffix  . . . . . . . : mydomain.local

        Node Type . . . . . . . . . . . . : Hybrid

        IP Routing Enabled. . . . . . . . : No

        WINS Proxy Enabled. . . . . . . . : No

        DNS Suffix Search List. . . . . . : mydomain.local

                                            localdomain

Ethernet adapter Local Area Connection:

        Connection-specific DNS Suffix  . : mydomain.local

        Description . . . . . . . . . . . : Realtek RTL8139 Family PCI Fast Ethernet NIC

        Physical Address. . . . . . . . . : 00-20-ED-26-FD-9A

        Dhcp Enabled. . . . . . . . . . . : Yes

        Autoconfiguration Enabled . . . . : Yes

        IP Address. . . . . . . . . . . . : 10.0.0.134

        Subnet Mask . . . . . . . . . . . : 255.255.255.0

        Default Gateway . . . . . . . . . : 10.0.0.1

        DHCP Server . . . . . . . . . . . : 10.0.0.254

        DNS Servers . . . . . . . . . . . : 10.0.0.1

        Primary WINS Server . . . . . . . : 10.0.0.1

        Lease Obtained. . . . . . . . . . : 26 April 2006 08:43:24

        Lease Expires . . . . . . . . . . : 26 April 2006 09:13:24

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Comment
Question by:paulmward
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6 Comments
 
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Accepted Solution

by:
Renato Montenegro Rustici earned 150 total points
ID: 16561484
I think that there is another DHCP on the network. This address could only be setup manually or by a DHCP server. Otherwise, it would be an APIPA address which is something like 169.254.0.0 (self-generated). So, there is a DHCP in place.

... Or ...

Please, can you try to disable or, better, uninstall RRAS for testing purposes? Iam suspecting it.
0
 
LVL 6

Expert Comment

by:marce_lito
ID: 16562539
i also think that there might be another dhcp server on your lan....

you could try downloading nmap (www.insecure.org), installing it and then type the following from the command prompt:

nmap -sU -p67-68 10.0.0.0/24

to see if any other machine has dhcp configured
0
 

Author Comment

by:paulmward
ID: 16562545
rmrustice

Even though I was certain, after your post I double-checked all of the servers again to make sure that none of them had the DHCP Server service running apart from the DC.

None of them did. However, one server had VMware DHCP service running.

VMware was installed about 2 weeks ago. About the same time as these problems occurred!!!

I checked the VMware config and noticed that on the virtual network I created to make one of the virtual machines accessible to the rest of the network, had DHCP service enabled and issuing default leases for 30 mins.

I am confident that this is going to resolve the problem. I've tested 2 of the 5 machines that were having the problem and they are now getting the correct settings from the correct DHCP server.

I'm going to wait until after the weekend though to make sure that it's definitely fixed. So if it is I'll award you the points on Tuesday.

Thanks,

Paul
0
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Author Comment

by:paulmward
ID: 16562717
marce_lito

Thanks for that little util. I can see that coming in handy in the future
0
 
LVL 6

Expert Comment

by:marce_lito
ID: 16563501
don't worry... you'll find that nmap is very useful pointing devices on your network... it has many uses, and you'll find yourself using it a lot =D
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Author Comment

by:paulmward
ID: 16587298
Thank all working this morning
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