cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
2969
Views
0
Helpful
2
Replies

DHCP server not handing out specific IP's

Eric Hansen
Level 1
Level 1

hello, I have a DHCP server for a subnet that has only lightweight WAP's in it.  The DHCP server is running on the gateway for this subnet which is a 3750X 2 switch stack running 12.2(53r)se2.

I have the following configured:

ip dhcp excluded-address 10.1.10.161 10.1.10.162

ip dhcp pool DHCP-VL20

   network 10.1.10.160 255.255.255.224

   domain-name mydomain.net

   dns-server 10.11.11.30 10.11.11.40

   default-router 10.1.10.161

   lease 3

The server hands out up to 18 IP addresses and no more, with 20 devices on the subnet.  Scanning the subnet with a 3rd party network management system I see the following IP's never get handed out or used:

10.1.10.161 - 162 (manually excluded)

10.1.10.167 - 168

10.1.10.171 - 176

10.1.10.178

and of course  2 IP's I have manually excluded, 11 IP's in all that wont get handed out.  It should only be 2 that don't get handed out.  I've double and triple checked the exclusion and thats the only one.  so I run a 'sh ip dhcp pool' and see this:

Pool DHCP-VL20 :

Utilization mark (high/low)    : 100 / 0

Subnet size (first/next)       : 0 / 0

Total addresses                : 30

Leased addresses               : 18

Excluded addresses             : 11

Pending event                  : none

1 subnet is currently in the pool :

Current index        IP address range                    Leased/Excluded/Total

10.1.10.166        10.1.10.161    - 10.1.10.190     18    / 11    / 30 

[edit]

I should also mention that "sh ip dhcp bind" does not show these randomly excluded IP's in use.  They also do not show up in any arp table I can find.

[/edit

I have looked all over the config and I cant find where these extra 9 addresses are being excluded.  Does anyone have any ideas how to free up these 9 seemingly random exclusions?  Haven't issued a reload and I haven't deleted and rebuilt the DHCP server yet, production network.

*confused*

Message was edited by: Eric Hansen

1 Accepted Solution

Accepted Solutions

cadet alain
VIP Alumni
VIP Alumni

Hi,

do they appear in the conflict logging ? ---> sh ip dhcp conflict logging

can you also show us the output of sh ip dhcp server statistic

Regards

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

View solution in original post

2 Replies 2

cadet alain
VIP Alumni
VIP Alumni

Hi,

do they appear in the conflict logging ? ---> sh ip dhcp conflict logging

can you also show us the output of sh ip dhcp server statistic

Regards

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

AHH!  That was it, they were in the conflict list.  I ran a "clear ip dhcp conflict *" and everything is peachy now.  Thanks! 

Review Cisco Networking for a $25 gift card