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NSLOOKUP & PING return incorrect IP address on LAN

Posted on 2012-03-21
8
1,096 Views
Last Modified: 2012-03-21
SBS2008 network. The SBS box is in charge on the LAN, running DHCP & DNS.

The network is 10.0.100.x
Subnet 255.255.255.0

PC1 has dynamic IP 10.0.100.11
PC2 has dynamic IP 10.0.100.15

All PCs and servers on the network resolve PC1 & PC2 to 10.0.100.11

There are no hosts or lmhosts entries
I've stopped DNS & DHCP on the SBS box, cleared the DNS resolver cache, released IPs on the clients, restarted DHCP & DNS and reconnected the clients. Same result.

I'm baffled.

Please unbaffle me.
0
Comment
Question by:snooflehammer
8 Comments
 
LVL 3

Expert Comment

by:AirShield
ID: 37750951
What are the names of PC1&2??

Just to test, try adding 10.0.100.11 & 10.0.100.15 to dhcp exclusion list, renew the leases and reset the networks adapters. What happens after the test?
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Author Comment

by:snooflehammer
ID: 37750971
PC1 is called CAMERAS
PC2 is called WS10

I excluded the addresses and forced renewal. They both got different IPs. NSLOOKUP still returns the old IP of 10.0.100.11 for both of them.

Server has 30 updates outstanding. Guess I'll apply them...
0
 
LVL 3

Expert Comment

by:AirShield
ID: 37750976
where are running nslookup from?? does this behavior happens from every PC?

It sounds like a DNS issue, have you tried rebooting the sever after the test?
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Author Comment

by:snooflehammer
ID: 37751000
Every PC on the network. I agree it's DNS-related.

The server is going to reboot once the patches have installed.
0
 
LVL 3

Expert Comment

by:AirShield
ID: 37751006
Ok, post back after the reboot.
0
 
LVL 57

Accepted Solution

by:
Cliff Galiher earned 500 total points
ID: 37751033
Nowhere in your list of things that you did do I see that you removed any DNS records. I'm guessing that if you open the DNS administrative snap-in and view all of the DNS records you will find one that references the PC name you are using and the wrong IP. DHCP will *add* records, but it doesn't delete old ones, and it is legal for one machine to have multiple IP addresses in DNS (for load balancing, round-robin resolution, and other advanced topologies) so that old record can hang out there indefinitely if you don't manually remove it.

Do that, THEN flush the DNS resolver cache, and I think you'll see things start working.

-Cliff
0
 
LVL 4

Expert Comment

by:ltsweb
ID: 37751048
Agree with Cliff!  Check DNS and expand the domain and you will likely find both machine names with same IP.  Delete the one that is incorrect, right click on server name in DNS, Scavenge, and Clear Cache.

See: http://blogs.technet.com/b/askpfe/archive/2011/06/03/how-dns-scavenging-and-the-dhcp-lease-duration-relate.aspx  for an explanation.
0
 

Author Closing Comment

by:snooflehammer
ID: 37751052
In all my years of dealing with Windows servers, and it's been a few, I never knew you could do that. Always happy to learn.

Thanks, man
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