DHCP full, but not?

Question

_{Wednesday, April 3, 2013 12:32 PM}

I have several scopes that are reported as full.

However, when i go in and check the leases i can see several free ones.

How come, and what can i do to fix the problem?

Tor Arne

All replies (5)

_{Wednesday, April 3, 2013 12:54 PM}

Seems like when a satellite server lose his connection to GC/DC the DHCP wont hand out more ip's.. even after the connection is up.

Restarting the service does not help.

Only thing that helps is to restart the server.

Suggestions?

Its Windows server 2008R2

Tor Arne

_{Thursday, April 4, 2013 8:13 AM}

Hi Tor,

Firstly, please check if there is any related error in Event Viewer. Please provide us detailed error messages.

Also, please let us know the following:

1. Do you enable any other server role in the DHCP server?

2. What is the role of the satellite server?

3. A network diagram is appreciated.

In addition, hope the following could help:

Troubleshooting DHCP servers

http://technet.microsoft.com/en-us/library/cc779112(v=ws.10).aspx

Increasing the number of IP addresses on a subnet in DHCP Server

http://support.microsoft.com/kb/255999

Hope this helps.

Jeremy Wu
TechNet Community Support

_{Thursday, April 4, 2013 11:13 AM}

1. Do you enable any other server role in the DHCP server?

DHCP, PRINT and DFS.

2. What is the role of the satellite server?

On another site for dhcp and print mainly.

If i check a net in dhcp.. example..

192.168.0.0/24

when 1-254 is in the pool, and 1-3 is excluded.

If you check the statistics it says 0 free.

But if you check the leases, there's a lease on 4,7,10,11,15,18 and so on.

As you can see, there's ALOT free.. but for some reason it doesnt count them as free?

_{Friday, April 5, 2013 9:41 AM}

Hi Tor,

Thanks for the reply.

What is the relationship of the two DHCP servers in the two sites? Do they host the same DHCP scopes? What is the configuration?

Also, if there are clients have static IP addresses configured, it is possible that you cannot see the lease information in DHCP management console. You can try to ping these IP addresses to see if they are “active”.

Hope this helps.

Jeremy Wu
TechNet Community Support

_{Monday, April 8, 2013 1:00 PM}

Hi,

We have several sites which all have DHCP,PRINT and DFS.

I kinda understand more of the problem now.

We are using superscopes, and each server have diffrent scopes.

If a /24 net is full, it moves on to the next one.

However, the free count on the first superscope is not updated untill the server is back at this scope.. kinda... Understandable?

scope1 full (if you go in and check, you might find 50 ip's free)

scope2 full (if you go in and check, you might find 50 ip's free)

scope3 3 free.

If scope 3 gets full, it updates statistics on scope1, and hand out free ips.

Tor Arne