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DHCP problem: clients given NACK for dhc

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5 replies

by wml

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Clients are losing their connections: seems that they are not finding dhcp server.
WINIPCFG on client reveals dhcp server as 255.255.255.255

This happened straight after a server reboot. The wierd bit is that the clients appear to be requesting the server's ip address.
DHCP log after reboot shows:
11,12/14/00,18:16:53,Renew,x.x.x.54,drawing,005004361976
15,12/14/00,18:16:54,NAck,x.x.x.8,drawing,005004361976
i.e. client called drawing ip address .54 is renewed and 1 second later receivesa NACK but with its address shown as x.x.x.8 which is the address of the dhcp server.

Any suggestions/fixes appreciated.

5 replies

by gbjoe

Try reconciling the DHCP database (in the scope properties, click on the reconcile button). This will clean up the database.

Hope this helps

by wml

I discovered that our proxy server had switched on its own dhcp service which was in conflict with the NT one. Explains everything!

by lee_mikej

When a client looks for a DHCP server it sends a brodcast message requesting the servers DHCP IP address. A broadcast uses always uses the IP address 255.255.255.255.

Please check that the Server's IP address isn't included in the DHCP lease scope, if it is in the same range, add the servers address to the excluded list.

Failing that please provide the following information, Servers IP addr & Subnet mask, DHCP scope & Subnet mask.

Cheers Mike.

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