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DHCP pool excluding more addresses than are on the exclusion list

KJ-NYC
Level 1
Level 1

I have several DHCP servers configured on my 9300 switch stack, and they are all operating well. One of them has run out of IPs in its /22 DHCP pool due to an exclusion that I cannot get to the bottom of. It is excluding 337 IPs:

 

 

 

Pool WiFi :
 Utilization mark (high/low)    : 100 / 0
 Subnet size (first/next)       : 0 / 0 
 Total addresses                : 1022
 Leased addresses               : 685
 Excluded addresses             : 337
 Pending event                  : none
 1 subnet is currently in the pool :
 Current index        IP address range                        Leased/Excluded/Total
 0.0.0.0              10.224.104.1     - 10.224.107.254    685   / 337   / 1022 

 

 

but there are only 4 exclusions listed in the config:

 

 

#sho run | inc excluded
ip dhcp excluded-address 10.224.209.1 10.224.209.19
ip dhcp excluded-address 10.224.210.1 10.224.210.19
ip dhcp excluded-address 10.224.211.1 10.224.211.19
ip dhcp excluded-address 10.224.102.1 10.224.102.9
ip dhcp excluded-address 10.224.102.200 10.224.102.254
ip dhcp excluded-address 10.224.103.1 10.224.103.19
ip dhcp excluded-address 10.224.100.1 10.224.100.99
ip dhcp excluded-address 10.224.110.2 10.224.110.10
ip dhcp excluded-address 10.224.104.1 10.224.104.4

 

 

 What would be causing this exclusion if it is not explicitly listed?

 

1 Accepted Solution

Accepted Solutions

KJ-NYC
Level 1
Level 1

Thanks for the quick responses, guys. We were able to figure it out. It turns out that when the DHCP server sees an IP conflict, it adds the conflicting IPs to the exclusion list, and they stay there until explicitly removed. We were able to clear the list with the 

clear ip dhcp conflict *

 command, and voila! the exclusion list matched the config exclusion number. 

View solution in original post

5 Replies 5

What is the mask for this dhcp pool?

MHM

Richard Burts
Hall of Fame
Hall of Fame

Not sure what is causing this. Could you post the complete current running config, obscuring any sensitive information (passwords, Public addresses, etc).

HTH

Rick

KJ-NYC
Level 1
Level 1

Thanks for the quick responses, guys. We were able to figure it out. It turns out that when the DHCP server sees an IP conflict, it adds the conflicting IPs to the exclusion list, and they stay there until explicitly removed. We were able to clear the list with the 

clear ip dhcp conflict *

 command, and voila! the exclusion list matched the config exclusion number. 

And after some time the conflict table full again.

There is issue friend 

Anyway if it appear again let me ķnow

MHM

Thanks for the update. Glad that you were able to resolve the issue.

HTH

Rick
Review Cisco Networking for a $25 gift card