dhcp - excluded address range

[JMCNEL]

we have a 3560 switch configured with EIGRP with dhcp.  We have a user that we cannot ping, however the interface show up / up and no errors on interface. the ip address is 10.2.0.199 - however we have dhcp configured to exclude the range from dhcp

ip dhcp excluded-address 10.22.0.1 10.22.0.200

how can this work station get a dhcp address if we have that ip range excluded from the dhcp pool?

The user is off a different switch that is a uplink to this distribution switch. Traceroutes shows that the problem is with the distribution switch.

[John Blakley]

Since this user is on a different switch, do you have another dhcp server on the switch that they're connected to? Also, can you do a "sh ip dhcp bind" and see if you can see the address assigned to that host? Did you do the exclusion after bringing up the scope? If so, you may have assigned the host before the exclusion was done. In that case, the host wouldn't get a new address until their lease had expired.

HTH,

John

[JMCNEL]

no we only have dhcp configured on the distribution switch

when I do the so ip dhcp vrf xxx binding - i dont see the binding right now.

I cant remember when the exclusion was put in place - probably 2 years back

thanks for your response

[tim.giles]

Hi,

What type of host is connected to the switch?

If it's a PC, can you try a release/renew and see if the switch issues a new IP address via DHCP.

..do you mean the IP of your host is 10.2.0.199 or 10.22.0.199?

Tim

[Peter Paluch]

Hello,

As other friends discussed here, the ip dhcp excluded-address is valid only for new leases, not for leases that already have been assigned. You may even need to issue the clear ip dhcp binding * command to force the DHCP server to forget individual assigned leases and start assigning new IP addresses according to the current configuration, including the excluded address ranges.

There are two independent issues being solved here, in my opinion - you are complaining that the PC is assigned an IP address via DHCP that should not have been assigned at all. The second issue is that the PC itself can not be pinged. But is it certain that this IP address is indeed assigned via DHCP? Also, you have metnioned running the show ip dhcp vrf XXX binding - do you run your DHCP pools in VRFs? Are the interfaces in correct VRFs as well, then?

Perhaps posting the configuration of the device that runs the DHCP server would be helpful here.

Best regards,

Peter