Hello Dear I have reserved IP in dhcp scope, but still it could not get ip from dhcp, when i check the log, there nack is showing, i remove reservation then it gets ip from other scope (as i am using superscope), if i give static ip (that i reserved) it works fine, but on coming back to dhcp, it again starting giving nack. Kindly help me as this is very urgent

reserved ip means you associated that ip with a particular mac address. Doesn't sound like you did this. Just putting addresses into a reserved pool means they don't get assigned to anything.

Dear Wanderer Thanx for ur reply, dear i have reserved the ip with their corresponding mac addresses and mentioned problem does not always occur i.e some time it gets ip and some time not, it sometime happens so that if the client is not getting ip from dhcp reservation, i just delete the reservation and reserve another ip with same mac and the client gets the ip... i have verified by pinging and nslookup that no one is using previous ip. Waiting for ur kind help...

i am using superscopes, i have heard that this issue happens with superscope i am not sure that either this is happening because of superscopes or not, but its not possible for me to remove superscopes. plzzzzzzz help

I think perhaps your dhcp server is overworked. I would bring up two dhcp servers each with half the superscope and see if that makes a difference.

i dont think so that it is so i have : scopes = 31 total addresses = 948 in use 441 (46%) available 507 (53%) Where as i read somewhere that they tested on 5000 scopes and they worked fine