PCs resolving to Old IPs.

February 23, 2011 at 06:24:55
Specs: Windows XP
Hello,

We have Windows XP client PCs and Window Server 2003 Servers. There is this problem I am facing. Before joining a computer A to the domain I can ping to Computer B (which i changed from old ip to new ip). After I join to the domain, i can no longer ping to the computer B, it tries to ping to the old IP instead. We have a WINS setting and DNS settings configured on these PCs.

After joining the domain, I changed the DNS ip provided to me by the System administrator and used an IP of a server which i found using WireShark. When I did that and pinged computer B , the computer A was able to ping to it successfully when it was on the domain.

Before I speak to the system administrator about this issue, i wanted to asked what exactly is causing this problem. We are in a network of 200+ PCs. This happens to all pcs. If i ping from any PC to any PC which have there IPs changed face this problem. It resolves to the old IP.

Thanks in advance.


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#1
February 23, 2011 at 07:13:04
Sounds like computer B is not in your DNS. Check your DNS host (A) records to make sure computer B is there. If it is take note of the IP that is registered, it may be wrong.

The other problem could be that Computer A is not getting the right DNS. Can you send us Computer A's IPCONFIG /ALL?

Another thing, could be the local DNS cache on computer A is not being refreshed. Try flushing and reregistering.

ipconfig /flushdns
ipconfig /registerdns

"After joining the domain, I changed the DNS ip provided to me by the System administrator and used an IP of a server which i found using WireShark."

Why are you using Wireshark to discover the DNS. Is it not showing up in your NSLOOKUP or your IPCONFIG? If not then that can be your problem.


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#2
February 23, 2011 at 07:19:25
If you are using manual IP addresses then someone needs to update the address on the DNS server. It's also advisable to do a

ipconfig /flushdns

on the computer that you are pinging from, to make sure that its resolver cache is flushed.


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#3
February 23, 2011 at 07:29:13
I have ipconfig /flushdns and /registerdns
Even after that it still doesnt ping. I tried this with two computers that were already on the domain.
Computer C and Computer D are on the domain. We relocated Computer C to another floor and changed its IP. We rejoined the PC to the domain, did /flushdns. It has been a week now and still i cannot ping to computer C from computer D. I Tried to ping from Computer E to Computer C also and still it failed. Always tried to ping to the old IP.
So i came up with an idea to try removing Computer D from the domain and add it to a workgroup. I tried that and it it resolved correctly Computer C to its new IP. I tried the same for computer E, removed from domain, added to workgroup and it worked.

I tried it also with a freshly XP installed PC. When it was on the workgroup i could ping to Cmputer C, once i added it to the workgroup it stopped ping and tried to resolve to Computer C's old IP.
It cant be from the client end since it happens to a new PC also. This problems happens even i tried the other way round..i.e. if computer D's IP was changed and i tried to ping from Computer C and E.


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Related Solutions

#4
February 23, 2011 at 07:33:32
Do you have Firewalls between the floors. If so they could be blocking DNS UDP port 53 causing the computer to not be able to communicate with the DNS server.

Other wise I would be looking at your IPCONFIG /ALL to make sure they are set to the right DNS. If they are try pinging it. If not then look into how you have your DHCP setup.


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#5
February 23, 2011 at 07:54:36
Nothing between floors. This problem happens also for computers within the same floors also.
Our system admins recently changed DNS Servers so the DNS servers IPs had changed if that is of importance. Of course we made the required changes on the client PCs to change the primary and secondary DNS IPs. During this time i believe, though not sure, the problem started.
We have the right DNS IPs setup for primary and secondary. It does show up in ipconfig /all. It pings properly to these servers.
We use static IPs for the computers BTW.

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#6
February 23, 2011 at 08:35:12
"We use static IPs for the computers"
"still i cannot ping to computer C from computer D"

TGBOY workstation membership has nothing to do with DNS. This unjoining and rejoining the domain accomplishes nothing because you are not dealing with a workstataion/domain trust issue.

You don't clarify whether you are pinging by name or ip. I would assume both.

Not being able to ping by ip means a firewall is blocking. Review the workstations firewall config.
Not being able to ping by name means your dns server doesn't have a manual host record for this pc in DNS.

Since you are able to join pcs to the domain I have to think you only pinged by ip and the issue is solely that of workstation firewall blocking icmp.

Answers are only as good as the information you provide.
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#7
February 23, 2011 at 08:51:42
Sorry for not specifying how i am pinging.
When I ping by name it doesnt work. When i ping by IP it works.

"This unjoining and rejoining the domain accomplishes nothing because you are not dealing with a workstataion/domain trust issue."

When I ping to the computer name while it is a member of the domain , it resolves to the old IP. When i remove it from the domain and ping the computer name it resolves correctly to the new IP address.

"Not being able to ping by name means your dns server doesn't have a manual host record for this pc in DNS."

Like i stated above, when i ping to the computer name after removing from the domain, it pings correctly.

Does the resolving steps change when it is in the domain and when it is not in a domain?
DNS and WINS are present.


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#8
February 23, 2011 at 10:57:59
"Our system admins recently changed DNS Servers so the DNS servers IPs had changed if that is of importance. Of course we made the required changes on the client PCs to change the primary and secondary DNS IPs. During this time i believe, though not sure, the problem started. "

Yes

Try this to help you trouble shoot...

http://www.windowsnetworking.com/ar...


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#9
February 23, 2011 at 12:01:38
This all comes down to not changing the static dns host entries.

Why you can ping successfully by name when not on the domain would lead me to thing the dns host/ptr record had been deleted/wkst dns pointer changed and your experience was a result of final name resolution : broadcasts and the unjoined machine answered.

Who is responsible for updating the static dns entries? Anyone changing ips should have this ability.

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#10
February 23, 2011 at 12:45:54
Sounds like when you join the domain you change the domain part of the machine name. Hence it no longer has a DNS entry. In a Windows network it's really much easier to use DHCP and let the server take care of updating the DNS zones automatically (I assume that you are using the Windows DNS server rather than some other one). You only need fixed addresses for servers, and even then it's not essential for all of them. As long as your DNS server has a fixed address everything else should work.

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#11
February 24, 2011 at 05:48:46
ok I tried this,
I removed both the Primary and Secondary DNS entries from my PC, leaving only the WINS server IP as it is, while my PC is still a member of a domain.
When i tried pinging the name of the PC this time it worked without any issues. When i put the DNS entries back, it stopped working.

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#12
February 24, 2011 at 08:19:24
That would be correct. Name resolution didn't get answers until it did broadcasts which the pc responded to.

You can't fix this until you fix dns.

I take it you don't have access to the ms dns servers. You need to bump this up to who does have control.

You are wasting your time until you do so.

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#13
February 24, 2011 at 08:19:51
Try DHCP.

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#14
February 24, 2011 at 08:33:17
Yea i had a doubt it was the DNS , i just wanted to make sure i had tried everythin from the client end. We are the ones assigning new IPs when we change locations of the computers.
So what exactly in the DNS server is causing the problem. How can it be resolved.

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#15
February 24, 2011 at 09:07:49
Since you are not using dhcp with dns autoupdate this means you have to manually go into dns and remove the old host and prt record. Host record is in the forward lookup zone whereas the prt is in the reverse lookup zone.

Just like when you do a static ip assignment you have to make a manual static dns entry per new assignment.

Then you have to manually create the new host record [and check the box to create the ptr record].

Most likely have have a number of records that need to be deleted and recreated.

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#16
February 24, 2011 at 09:37:24
One question, new computers with new names and ip address joined to domain and resolve correctly.
BTW if i removed the computer name from the Active Directory Users and Computers , is it the same?

"Then you have to manually create the new host record [and check the box to create the ptr record]."

Is what you mentioned the same as deleting the host record and then rejoined the PC to the domain? Does that also automatically create a new record?

Lastly as you said for every PC we change IP the host and ptr record has to be recreated manually. No other way.


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#17
February 24, 2011 at 09:46:02
"Lastly as you said for every PC we change IP the host and ptr record has to be recreated manually. No other way."

That's why you should use DHCP! Let the server do the work of looking after IP addresses.


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#18
February 24, 2011 at 10:51:32
I don't think that DHCP would fix this problem. He has the right IP for the DNS assigned so all DHCP would have done was ensure that the NIC used the right DNS address. His problem is the DNS is resolving the wrong IP because they moved their DNS server. It sounds like like the computer is still resolving to the old DNS server or that there are old Host A records in his DNS that are giving him the wrong IP. The funny thing is this should be happening on all of the other computers too. This is probably because he is using a WINs server in conjunction with the DNS and the WINs server is resolving it. He needs to trouble shoot his DNS communications. I gave him all of my DNS trouble shooting techniques we just need another technique that might help.

Personally if it was me and I knew it was machine specific, I would just image another computer that is working onto the one that is having the problem and be done with it. But, then again all of our machines use like hardware that gives me that ability.


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#19
February 24, 2011 at 11:03:18
@ace_omega

Yes this happens on all computers on the domain that have the IPs changed. WINS server resolves correctly since as i mentioned when the DNS is removed it works correctly.
As wanderer said , i guess the host and ptr records have to be updated. Do all organizations who use static IPs do this for all computers tat they change IPs. Isnt there another way.
Like I asked before, does removing computer names from AD Users and Computers
and then rejoining the computer on the domain be the same.
New PCs with new computer names work properly until their IPs are also changed. Then the problem happens.


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#20
February 24, 2011 at 11:16:05
As mentioned by IJACK, you can do dynamic IP management through DHCP by setting up reservations for the MAC addresses on the computers NICs. This just ensures that for a given MAC it is always given that specific IP.

http://www.ehow.com/how_5593436_con...

I have a pure DHCP server network and use this technique for devices that need static IPs like Server and Printers. Seems to work well considering all of the other bugs in Microsoft DHCP.


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#21
February 24, 2011 at 11:22:39
My previous company did use DHCP, it was much easier. My present company uses static IPs for all workstations.
Oh i did want to mention on a specific floor we use DHCP to assign IPs. Even to these PCs i cant connect. The computer name resolves to the old IP even if DHCP assings the IP. Why is tat?

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#22
February 24, 2011 at 11:32:34
Its like I said, I don't think DHCP is your problem. You problems lie in the DNS. I know I asked this before but it sounds like something is blocking the DNS protocol but you said you did not have a fire wall. I know it is hard to do but check the wireshark DNS packets for problems.

I personally would start at the DNS server looking at the host A records to make sure they are right. I would look how your DNS is configured for reasons why it might not be registering new IPs for the FQDN in the DNS. (I think Wanderer mentioned this have you done it?)

http://www.windowsnetworking.com/ar...

As for how to do this automatically, it is in the nature of using static IPs that it is all manual. The only reason I see for using all static is to monitor computer usage to identify which computer is creating certain packets. But, it is not hard to do this with a DHCP server either because you can set large TTL and see which computer had the IP reserved in the DHCP. Might be a consideration.


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#23
February 24, 2011 at 14:08:05
"Do all organizations who use static IPs do this for all computers tat they change IPs. Isnt there another way."

We have static ips due to multiple wan connected sites and yes we update the static entries when needed [most are thin clients not joined to the domain and since they don't need name resolution for themselves - they just need to find the servers]

no there isn't another way.

TGBOY what is the issue here? Why don't you have access to the dns server?
This issue would have already have been fixed if you had done as advised.
why do you keep going round and round about this?
why are you not talking to the network admin about this?
Surprised he isn't talking to you since the dns error logs must be getting full with errors.

Ace is correct that dhcp unto itself wouldn't address the issue. That is way the second step, engaging dhcp to autoupdate dns, is the final step in allowing the system to maintain these records for you.

I am guessing you have to change subnets with these moves and no one knows how to enable dhcp relay on the routers dividing the subnets which is why dhcp was never setup in the first place.

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#24
February 24, 2011 at 21:37:17
Yea i did bring up the issue with the system admin, he just said to do a ipconfig /registerdns and it would work.
I told him it didnt work.
Anyways I will get back to him on Tuesday regarding this issue and see what happens.

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#25
February 25, 2011 at 12:12:04
http://technet.microsoft.com/en-us/...

might have the admin review the troubleshooting section of this link

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#26
March 11, 2011 at 00:56:49
Thanks for the replies. It was the DNS entried.

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#27
March 11, 2011 at 06:46:47
Thanks for the update.

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