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DHCP and W2K

I have a network that uses routers as dhcp servers for remote stations - 25/2600s. The dns servers ip addresses was changed and ca't seem to get the W2k PCs to renew their ip details. There seem to be issues with W2k PC and cisco dhcp. Any experiences. How can I 'flush' the address to force the PCs to renew their addresses. Looks like interoperability issues. Pls help!



Cisco Employee

Re: DHCP and W2K

There are no issues like that reported. Looks like Win2K may be caching it. You need to issue "Release All" in "winipcfg" on windows PC and then "Renew All". That should make the Win2K to send fresh dhcp broadcast.

Now what does happen if you reboot that PC? Does it gets new DNS server ip address?

Now you can enable following debug on a router to see what is being allocated

debug ip dhcp server events

debug ip dhcp server packets

debug ip dhcp server linkage


Re: DHCP and W2K

Thanks for the response.

What happened is that the dns address got changed in the scope on the router and the PCs could not get the new ones thus mail and www had problems.

The ones that expire gets the new addresses and work but the ones yet to expire could not. some shows after "ipconfig/release" is done but gets back the old thing when u do "ipconfig/renew"

I think dhcp clients tries to verify (or something) their parameters after 50/75 % of it's lease period and that's when problems comes.

Looking at reducing lease time to 1-2 days in other stations to avoid issues. They are many!

Lastly the "ip nameserver *.*.*.* " command in routers, do they affect dns in dhcp scopes?

Thanks in advance.

Cisco Employee

Re: DHCP and W2K

You need to use "dns-server x.x.x.x y.y.y.y" command under the "ip dhcp pool name" command to allocate dns servers under that scope.

ip name-server xxxx command is a global command which dosen't fall under any dhcp scope. dns-servers configured under the scope will overwrite that.

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