topic Re: DHCP Binding Issue - Help!!! :/ in Switching

DHCP Binding Issue - Help!!! :/

maback — Fri, 08 Mar 2019 01:35:07 GMT

I am having issues with getting clients to obtain a static DHCP binding which I have applied on the site Core switch (also acting as the site DHCP server).

-------------------------------

CoreSwitch#show run

ip dhcp pool xxxx

network 10.100.1.0 255.255.255.0

default router 10.100.1.1

domain-name xxxx

dns-server 10.x.x.x 10.x.x.x 8.8.8.8

ip dhcp pool binding_x

host 10.100.1.44 255.255.255.0

client-identifier d4c9.ef50.9e10

client-name x

-----------------------------

Troubleshooting steps followed so far:

1. issue a 'clear ip dhcp binding 10.100.1.216' on the the core switch

2. perform an ipconfig /release & /renew on the Windows 7 client laptop

3. reboot the laptop

4. Substituted the 'client-identifer' field with the 'hardware-address' field in the config (and also repeated steps 1-3)

No matter what, the client machine keeps getting the orginal DHCP lease it had before the binding was cleared (10.100.1.216).

Does anyone have any other ideas on how to solve this issue? Thanks!! 🙂

Re: DHCP Binding Issue - Help!!! :/

Sebastian Helmer — Wed, 15 Jan 2014 18:07:20 GMT

What Happen if u exclude the IP from the DHCP offer, do he get another one?

Sent from Cisco Technical Support iPad App

DHCP Binding Issue - Help!!! :/

cadet alain — Wed, 15 Jan 2014 21:08:18 GMT

Hi,

do this:

clear ip dhcp binding 10.100.1.216

ip dhcp pool binding_x

no client-identifier d4c9.ef50.9e10

client-identifier 01d4c9.ef50.9e10

Regards

Alain

Don't forget to rate helpful posts.

DHCP Binding Issue - Help!!! :/

maback — Thu, 16 Jan 2014 09:58:14 GMT

Hi Sebatsian & Alain,

Thanks for your advice, I've tried both of your suggestions, but it's still not working... the PC is now getting 10.100.1.225 (as opposed to .216)

Any other ideas?

Thanks!

Matt

DHCP Binding Issue - Help!!! :/

maback — Thu, 16 Jan 2014 13:11:35 GMT

Hi Sebastian & Alain,

I've now figured this out, the configuration appears to require the '01' appended to the start of the MAC address to recognise that the client media type is using an Ethernet controller, without this the DHCP server wasn't recognising the DHCP request from the client.

All working now, thanks for your input! 🙂

Matt

DHCP Binding Issue - Help!!! :/

cadet alain — Thu, 16 Jan 2014 13:40:06 GMT

Hi Matt,

This is exactly what I told you to do in my previous reply:

Hi,

do this:

clear ip dhcp binding 10.100.1.216

ip dhcp pool binding_x

no client-identifier d4c9.ef50.9e10

client-identifier 01d4c9.ef50.9e10

Regards

Alain

Regards

Alain

Don't forget to rate helpful posts.

DHCP Binding Issue - Help!!! :/

maback — Thu, 16 Jan 2014 15:15:57 GMT

Hi Alain,

Apologies, I did not pick up on that in your initial reply, but yes you are correct!

Thank you.

Matt