clear ip dhcp bindings

[nygenxny123]

"clear ip dhcp binding a.b.c.d-Clears an automatic address binding from the DHCP server database"

does this force the host to lose its IP

address and request a new ip via dhcp?

[prakkdangc]

Yes.

[nygenxny123]

really?

I issued a

clear ip dhcp binding *

command and i was still able to

ping hosts who learned their ip's from dhcp

[twistedsab2]

the hosts or end devices will keep using that assigned ip address, subnet mask, and gateway until the dhcp lease expires! even if you completely remove the dhcp server. this is by deisgn. however dns does not work like that you must have a dns server up and running at all times, or redundunt configurations in place so if dns1 fails then look for for alternative dns.

[Leonardo Oliveira]

Router# clear ip dhcp binding {address | *}

Deletes an automatic address binding from the DHCP database. Specifying the address argument clears the automatic binding for a specific (client) IP address, whereas specifying an asterisk (*) clears all automatic bindings.

[Edison Ortiz]

It will clear the dynamic bindings at the server but the server won't inform the client to clear its IP Address. To clear the IP address at the client, you must issue IPCONFIG /Release followed by IPCONFIG /Renew (if running a Windows Machine).

Regards,

Edison

[pauldaniels]

Would it be correct to say that performing a shut, no shut on the interface would cause the client to lose its address and need to send a new dhcp request?

Or would the client (a Windows machine, for example) be able to continue using the old lease?

[4bsmith]

It would retain the current address.

[Geoff Griffin]

Better late than never.

I had an issue just today whereas the dns servers that we point to were changed, I updated the static DNS on the router (and the dhcp pools) and was forced to clear the client DHCP lease.

The command to clear the client leases is:

clear ip dhcp pool <NAME> binding *

Hope this helps anyone with the same problem.

- Geoff

[gondelach]

No it doesn't. The command is for loosing the bindings, the clients don't know and you have to wait for a new dhcp packet from the client.

I was looking how to do a new dhcp request from the cisco itself, so when one of the cisco interfaces is configured as a dhcp client.

Then this is what you need, from enable mode just type:

release dhcp Fa0/1

renew dhcp Fa0/1

where Fa0/1 should be replaced with your interface.

A shut and no shut of the interface will have the same affect.

Did you still need the answer after 8 years? ;-)

[tyson.silvester]

Only posting for future researchers. A whole lot of mis-information on this forum. That doesn't do it either. That will only release/renew the IP given to that interface, not the client connected to it. 

https://www.cisco.com/c/en/us/td/docs/ios/12_2sb/12_2sba/feature/guide/sbahcprr.pdf

However, in my experience a shut/no shut will force the client to resend the dhcp request. 

[aso borit]

oke