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Windows DHCP server issues

Posted on 2014-01-09
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Last Modified: 2014-02-11
We are having issues with our DHCP server just failing out of the blue. At least once a day our DHCP server on our DC just stops working. It requires us to reboot the server in order for DHCP to start working. We have tried moving the service to another physical server, but still have the same problem. We then rebuilt our DHCP from scratch which also gave us the same results a day later. I cannot find anything any clues in  Event Viewer and havent found anything online. Has anyone had this issue before, or do you have any troubleshooting techniques you can pass along. Any help is appreciated.

Thanks!
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Question by:Vardata
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Expert Comment

by:aindelicato
ID: 39768617
Does the service stop? Does it error out and say it is not authorized?

Is this a workgroup or domain environment?

Is your lease space large enough?
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Assisted Solution

by:arnold
arnold earned 375 total points
ID: 39768639
Make sure you do not have another DHCP running on the network from a router/firewall that was mistakenly activated.

You could use wireshark or microsoft network monitor tool to look at network traffic to see if there is an errant DHCP server on the network outside the ones you know about.
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Author Comment

by:Vardata
ID: 39768719
No the service does not stop. When we try and open the DHCP database it wont open. There arernt any errors that come up. This is a Domain environment. Yes our lease space is large enough.
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Expert Comment

by:Patricksr1972
ID: 39768732
Hi

I believe arnold i right, i also suspect another DHCP server on the LAN, maybe some Wifi AP ??
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Expert Comment

by:aindelicato
ID: 39768739
Run ipconfig/all on a few machines to see if dhcp server is something other than what it should be.
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Expert Comment

by:tmoore1962
ID: 39768912
Another check to see if there's another dhcp server in the network is check the DHCP server service and see if it is stopped.  Since you have moved DHCP to another physical unit it has to be something in the network.  Depending on what you have for a firewall it may have a dhcp server running also which would cause the server's dhcp to stop.  When the server DHCP is stopped or you can stop the dhcp service manually then go to a workstation and open a command prompt and do IPCONFIG /release *  then a IPCONFIG /Renew * once the unit has an IP do IPCONFIG /all and note the IPaddress of the dhcp server to see if there's another dhcp server running.
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Assisted Solution

by:aindelicato
aindelicato earned 125 total points
ID: 39768926
Awesome users like to plug in linksys routers and things of that sort at their desks not realizing that they are spinning up DHCP.
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Author Comment

by:Vardata
ID: 39769908
Just an update to answer some possible solutions,

The DHCP service still shows as running, but when you go into the DHCP console to configure it, the DHCP server never opens, the hourglass just keeps spinning on the server in the DHCP console. When I try to restart the service, it times out and the only way to restore the service is to restart the whole server.

This issue was happening prior to moving the DHCP service to a new server, so that isn't the issue.

There is not another DHCP server in our environment. I know this because when the service stops handing out IP addresses, I get a 169.254.0.0 address (APIPA) when I release and renew.

We have rebuilt the database on 2 separate servers, and both servers have the same issue where the service stops and cannot be restarted unless the server is restarted. This to me means that it is an issue on the network, or at least something not local to the server.

I've also removed all but the server we have DHCP on from the Authorized Servers, through both the DHCP console and ADSI edit.

The service freezes around 2 or 3 times a day, with no particular time, just randomly.

Lastly, we have a domain environment with 2 servers. 1 with Server 2003 and 1 with Server 2008 Standard SP2. Our Domain controller and DNS are on 2003, with our print, file, and dirsync on the 2008.
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Assisted Solution

by:arnold
arnold earned 375 total points
ID: 39769960
You might have forgotten to authorize the DHCP server.right click on the DHCP and select authorize.

Netsh DHCP show server
Is a command you can use to confirm
You should get a list of authorized DHCP servers in the AD environment.

http://technet.microsoft.com/en-us/library/cc772372(v=WS.10).aspx
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Author Comment

by:Vardata
ID: 39769975
I've authorized the server. In the console, when I right click on the DHCP and go to authorized servers, it's the only one in the list. I've also double checked in ADSI edit and it's the only one listed there too.
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Expert Comment

by:arnold
ID: 39770047
Right click on the DHCP server and check statistics.

What is your leasing time set to?
How many workstations do you have?
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Author Comment

by:Vardata
ID: 39770053
Leasing time is set to 8 days for Wired, and 8 hours for Wireless, which were defaults when I re-configured the server. 4 separate pools for 4 VLANs. Around 15 in 2 of the pools, then 5 in another, and depending on WiFi users, anywhere from 10 to 25 in the last pool.

I've completely rebuild the database from the ground up on both the server 2003 and 2008 at separate times. I rebuilt it on Server 2003, then it ran for about a day and crashed. After that I removed it from Server 2003 and rebuilt it on the Server 2008, and it did the same thing. I un-authorized each time I removed it and added it to a different server.

We will be running the Microsoft Monitoring tool tomorrow morning (Usually crashes overnight, and we have to restart the server in the morning to get it working again) to see if there are any DHCP requests while the server is down. Will post results tomorrow morning. (EST time)
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Expert Comment

by:arnold
ID: 39770065
Your issue is likely that you are running out of allocatable IPs.
8days for wired is might be too long.
8 hours for wireless might be too long.  You can check the properties of the DHCP to check.

How many IPs in your scope/s?
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Author Comment

by:Vardata
ID: 39770070
At most, we use 25 addresses in 2 of the pools. I've allocated 40 possible addresses to each pool. XXX.005 to XXX.045 for each pool.

Is it a known issue that once you run out of addresses that the service freezes and crashes? We've ran out of addresses before, and the server didn't crash. I'll make sure to check this too though and post the result tomorrow morning, along with the Monitoring tool results.
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Expert Comment

by:arnold
ID: 39770076
In your case the service simply stops issuing IPs as it has non left.


Not sure why you are limiting the scopes as you have.
Remove one of your exclusions to increase the pool while reducing the lease time and see if that resolves your issues.
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Author Comment

by:Vardata
ID: 39770080
We only have around 25 employees, and we use the XXX.060 - XXX.070 range as static IP addresses for our printers. But I will extend the scopes to XXX.005 - XXX.150 and exclude the XXX.060 - XXX.070 range.

P.S - Thanks for the advice, I've got a lot of things to try tomorrow. Feel free to keep suggesting things you think might be the issue, and i'll implement them tomorrow.
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Expert Comment

by:vivigatt
ID: 39774939
APIPA addresses are assigned when there is NO DHCP server answering.
http://en.wikipedia.org/wiki/Link-local_address

Since you are in an AD environment, the DHCP DB is stored in AD.
Since the DHCP fails on several servers even freshly installed ones, I would suspect a problem with DHCP's config in AD.

I would try to completely remove the DHCP config from AD and restart from there:

http://djadwinsvr.blogspot.fr/2013/04/managing-dhcp-servers-active-directory.html
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Accepted Solution

by:
Vardata earned 0 total points
ID: 39780482
We ended up putting the DHCP on one of our switches. This solved the issue. Not completely sure why the DHCP wasn't working on either Window Servers. Tried all of the suggestions, but it must have been something else.

Thank you for your help guys, sorry we couldn't solve the actual problem and had to take a different route.
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Author Comment

by:Vardata
ID: 39784331
I've requested that this question be closed as follows:

Accepted answer: 0 points for Vardata's comment #a39780482

for the following reason:

Solved on our own. DHCP on switches.
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Assisted Solution

by:arnold
arnold earned 375 total points
ID: 39780958
Sounds as though you may have HAD VLANed switches and needed to enabe DHCP relay agents on them to proxy/forward the requests and responses to and from the DHCP server.
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Author Comment

by:Vardata
ID: 39781411
That was already set up and working for 2+ years before we started having issues. The switches are Adtran 1544's with ip helper-address' enabled on each vlan interface. The helper-address' point to the DHCP server for UDP ports 67 and 68, bootpc and bootps respectively, as stated on the switch. In other words that wasn't the issue, but still a good thing to check if your DHCP server is outside of your subnet.

 This question has been solved and the answer/solution marked, please close this question.

Thank you
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Expert Comment

by:vivigatt
ID: 39784330
Sorry but the question has NOT been solved. You found a workaround and did not find out why you had your problem or how to solve it.
Did you actually tried my solution (cleanup AD from everything related to DHCP)?
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LVL 16

Expert Comment

by:vivigatt
ID: 39784332
Sorry but the question has NOT been solved. You found a workaround and did not find out why you had your problem or how to solve it.
Did you actually tried my solution (cleanup AD from everything related to DHCP)?
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Author Comment

by:Vardata
ID: 39784358
Your suggestion is to make sure we unauthorized old DHCP servers. I stated in an earlier post that I unauthorized the server from the DHCP console and checked with ADSI edit to verify said server was unauthorized. (I also went through the guide in your post just to verify, before I put DHCP on the switches and removed it from the servers, and came back with the same results). Please make sure you're reading all of my posts before you post a suggestion that I've already tried.

You're right, my question was not answered, but the servers no longer have DHCP installed, so even if someone posts another potential solution I won't be able to test it to see if it fixes the issue.

Normally, I know you guys don't like when a question is left open, so that is why i'm asking it to be closed. I can no longer dedicate anymore time to this post, so I will leave it up to you guys to close this if you would like.

Thank you for your help and suggestions everyone.
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LVL 16

Expert Comment

by:vivigatt
ID: 39784367
You did not understand my suggestion.
I did not mean only to unauthorize DHCP servers, but to CLEANUP AD from anything related to them. That is not the same thing.

What experts don't like here is to spend some time trying to help and to see the question closed without any point awarded and without the OP taking time to investigate some perfectly reasonable leads.

I understand that you cannot afford spending more time on that, but you should also understand that we all are busy and can't afford spending time "for nothing".

I'll try to remember your behavior next time I see one of your question. I may just skip it...
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Author Comment

by:Vardata
ID: 39784381
You mentioned removing DHCP's config from AD. When you said "I would try to completely remove the DHCP config from AD and restart from there:", I figured that the link was what you meant by removing the DHCP config from AD, and I followed the link step by step, but it did not solve the issue. I'm not sure what else I could have done to fulfill your suggestion, maybe it's just me. I did not ignore your post, I went through it and tried your suggestion, sorry if it seemed like I skipped over it.

I also did not mean to offend you or anyone else, I was merely stating that I can no longer test anymore solutions since this is a live environment and the DHCP services are removed from the servers. I know that when I asked you to make sure you read all of my posts, that may have seemed offensive, but I didn't mean it in that way. I said that because I want to make sure everyone is on the same page and up to date so we aren't posting the same suggestions. Other than that I politely asked for the question to be closed and then thanked everyone for their help (including you), since I know you guys are also very busy people.

Sorry if I offended you or anyone else.

Have a good day,

And again, thank you everyone for your help.
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Author Closing Comment

by:Vardata
ID: 39849695
Thank you everyone for your suggestions and help on this one. Unfortunately, we were not able to find out why the DHCP service was freezing and then stopped allocating addresses. I went over each suggestion to no avail. Microsoft would not help us without paying for a service contract, so we decided to take the easy way out and put DHCP on our switch instead.

Sorry we couldn't resolve the specific issue.

And again, thank you everyone.
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