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not able to ping DCHP server, even though client has an IP address

I am running windows 7, and have a win 2k3 DHCP server.  I have multiple Dell swithces in my network.   I have roughly 65 PCs, and for some strange reason, this morning, 5 PC's can't connect to my DHCP server.  I can't ping the server, I can't browse to it.  This happened 3 weeks ago and the only way I was able to resolve it is to replace the NIC with a new one.


When checking ipconfig, I have a good IP address, default gateway and the DHCP and DNS are both correct.  I can ping any other server on my network.

So here's what I do to fix the problem temporarily, I note the IP address of the client, shut it down, delete the IP from the DHCP server, then boot up the client, do a ipconfig /release
and then a /renew and if that doesn't work, I have to do hte /release again, shutdown the client, and restart it, and then it gets a different IP, and it works for that day.

So this has happened to 5 PCs in 2 days. Not sure what is wrong with my DHCP server as I'm assuming that's where the problem lies?

Any suggestions?

Thanks.
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afacts
Asked:
afacts
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2 Solutions
 
ryan_johnstonCommented:
Did it run out of addresses in the scope?  Try expanding the scope and see if that helps.

I've also run across it where I've had to recreate the DHCP scopes because it got corrupted somehow.
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afactsAuthor Commented:
I didn't run out of addresses, I'm using about 58% and have somwhere around 45% free.

Well,if it's corrupt, wouldn't everything be corrupt?

So since I'm talking about my main subnet, where all my PCs are on, how would I go about recreating the that scope?  Do I first delete the current scope and just create another one, jule like it, with everything the same?   Are there any commands I can run to see if it's corrupt?
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Suliman Abu KharroubIT Consultant Commented:
Basic areas to check :

1.Switch port where DHCP is connected to /cable.
2.Switch ports where the clients connected to.
3. event log related to dhcp service on the server.

sometimes client can't renew/obtain ip address until restarting the DHCPClient service.

Also, in clients machines, open NIC properties and make sure that no authentication is enabled in the NIC level. (see attached).
a.PNG
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afactsAuthor Commented:
I can't find the authentication section on my NIC, i looked everywhere.

Regarding the switches,  the DHCP server is a VM, and there are multiple swithces along the way, so not sure how to identify if the switches are the problem, besides, the 5 different PCs are connected via different switches, so I really don't think that's the problem.

I will check the event viewer again, as I looked at it before, but didnt see anything, but I will check again.
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Suliman Abu KharroubIT Consultant Commented:
Then forget about the authentication tab, it will not appear if the service called "wired auto config" is stopped.

To identify the problem source, install another DHCP service on another  member server and configure the same scoop on in. stop dhcp server on the first server and test.
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afactsAuthor Commented:
So basically, create another DHCP server and see what happens, right?

How do I setup 2 DHCP servers to be active at the same time?
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Suliman Abu KharroubIT Consultant Commented:
you can setup them in 20-80% rule.

make 80% of the address pool in the first server and 20% in the second server.

http://technet.microsoft.com/en-us/library/cc958936.aspx
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afactsAuthor Commented:
I definetly have a problem with my DHCP server, as it's happening every day, to about 2 to 5 PCs a day. I've attached a picture of what I get.
There some Ip's with no Name, and then I've never seen this before, but there's some IP's that say "bad_address" in the name field.

I guess I have no choice, but to move my DHCP server to another server?

Besides the above article, do you know of any other in depth article that describes with step by step instructions?  I'm assuming the only way to move it over is to do it after hours, right, so it won't affect the clients?

Is there a way to keep my DHCP server with certain scopes on the old server and just move certain scopes over to the new server?
DHCP.jpg
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Suliman Abu KharroubIT Consultant Commented:
bad addresses are usually for mobile devices (iphone,ipads....etc).. I saw them before, you can safely delete them.

for the migration process, you can create a new DHCP server with all needed scoops. and make sure you have a conflict detection enabled in the new server to prevent IP address conflict.

Conflict detection is simple ping the ip address before DHCP server offers it for clients. you can configure it on the advanced tab (server properties).

Once the new server is ready, stop the old server (only stop the dhcp service). this way clients will not be effected... client whom get IP addresses from the old server will keep their IPs until they tried to renew the IP and since the DHCP is stopped the renewal process will fail and the client will broadcast a dhcp request which will be replied by a DHCP offer from the new DHCP server.

summarize the steps:
1. install and configure the new server.
2.stop the old server. (DHCP service).

hope everything is clear...
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afactsAuthor Commented:
So why are those bad_addresses coming up, as for years now, that never occured.

Ok, so why can't I just export the dhcp database and import it in the new server?
Also, I would like to have 2 DHCP servers setup, so is there a detailed article on that, on how to do that?
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Suliman Abu KharroubIT Consultant Commented:
setp by step:

http://technet.microsoft.com/en-us/library/ee405264(v=ws.10).aspx

For bad addresses I dont think its a big deal, you can delete them...
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afactsAuthor Commented:
Now I have a bigger problem, as of 10 minutes ago, I have devices that are not getting an ip address from my server.  They get a random 169.254.228.x Ip address.  I have plenty IP addres in my DHCP server, as I saw that theres about 50% free.

Not sure what to do?  How do I fix this?
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Suliman Abu KharroubIT Consultant Commented:
Did you add new DHCP ? If not please do as per the previous comments  above
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afactsAuthor Commented:
what do you mean add?  I'm still using my current one, I didn't make any changes yet, I only deleted 2 really old servers that have not been in production now for years.
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afactsAuthor Commented:
here's a picture of my netservices, should my main DHCP server be included, as it's not?
dhcpproblem.jpg
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Suliman Abu KharroubIT Consultant Commented:
Install and configure DHCP server role in a new server using 80/20 rule
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afactsAuthor Commented:
For some strange reason, the server was deauthorized.  I authorized it and it's working, yes, I need to setup hte DHCP on another server, using 80/20 rule, but the problem is with my phone system, it uses a custom entry and I don't know what to enter in there, so I have to call my vender to obtain that information.
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Suliman Abu KharroubIT Consultant Commented:
Check members of ad group "enterprise administrators".... Only those members can authriose/deauhtrise DHCP server
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afactsAuthor Commented:
I think maybe what did it is, when I removed the old servers from the netservices, maybe that caused it to deauthorize itself?
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Suliman Abu KharroubIT Consultant Commented:
I could be, but I am not sure of that...
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