DHCP Pool error

eash · ‎12-22-2014

Dear All,

I have L3 switch configured as DHCP server for 5 pools. For one of the pools the the leased IP shows as 4294967275. The capture is enclosed.

Request you to kind support for this problem.

Regards,

Eash

Peter Paluch · ‎12-23-2014

Eash,

There is a couple of things that surprise me in the snapshot you have posted:

The two DHCP pools displayed have the same name "DHCP21", just the one on the top of the screen has a strange "apostrophe" shown as as a tiny dot at the very top line below the terminal window header. Is that a JPG artifact, or do you really have two pools called DHCP21, or perhaps DHCP21-and-something?
The number of leased IP addresses is truly strange - in fact, it is the maximum number that can be expressed in an unsigned 4B integer variable, that is, 2^32 - 1. That could possibly indicate a software bug.

In any case, does the DHCP pool with the 192.168.210.0/24 network currently serve any addresses? If it does then this is some kind of a cosmetical bug - you should be able to report it to TAC but otherwise, I would not bother too much with it. To remove it, you could try removing the pool configuration completely, then putting it back. Beware, however, that this will also cause the DHCP server to possibly lose track of the leased addresses in that pool, so conflicts could ensue. Another take on this would be to reload the device - but this is a last resort suggestion.

Best regards,
Peter

eash · ‎12-25-2014

Hi peter,

Thanks for the reply and sorry for the delay in responding.

The dhcp pool are 100 and 110.

The user in the VLAN 100 are getting their IP's from the dhcp pool 192,168.210.0/24. Few users are able to obtain the IP address. But I am worried it should not affect other VLAN and users.

Please find enclosed the capture of the sh ver and correct sh ip dhcp pool.

Rebooting the device is not possible as it working enviroment.

Any other suggestion is welcome.

Regards,

Eash

Peter Paluch · ‎01-03-2015

Hi Eash,

Thank you for the additional info. Unfortunately, the data shown in the screenshots do not make any more sense to me than they do to you.

Is it possible to post the complete configuration of the switch please? Of course remove sensitive information such as passwords etc. If that is not permissible, can you at least post the configuration of all DHCP pools and excluded ranges? I am grasping at straws here, as the show command outputs are simply illogical.

Thanks!

Best regards,
Peter

eash · ‎01-07-2015

Hi Peter,

Please find the DHCP config enclosed.

ip dhcp remember
ip dhcp conflict resolution
ip dhcp excluded-address 192.168.210.1 192.168.210.31
ip dhcp excluded-address 192.168.210.160 192.168.210.254
ip dhcp excluded-address 192.168.211.1 192.168.211.31
ip dhcp excluded-address 192.168.211.160 192.168.211.254
ip dhcp excluded-address 192.168.212.1 192.168.212.31
ip dhcp excluded-address 192.168.212.160 192.168.212.254
ip dhcp excluded-address 192.168.213.1 192.168.213.31
ip dhcp excluded-address 192.168.213.160 192.168.213.254
ip dhcp excluded-address 192.168.214.1 192.168.214.31
ip dhcp excluded-address 192.168.214.160 192.168.214.254
ip dhcp excluded-address 192.168.209.1 192.168.209.31
ip dhcp excluded-address 192.168.209.160 192.168.209.254
!
ip dhcp pool DHCP210
network 192.168.210.0 255.255.255.0
default-router 192.168.210.200
dns-server 192.168.200.199
!
ip dhcp pool DHCP211
network 192.168.211.0 255.255.255.0
default-router 192.168.211.200
dns-server 192.168.200.199

!
ip dhcp pool DHCP212
network 192.168.212.0 255.255.255.0
default-router 192.168.212.200
dns-server 192.168.200.199

!
ip dhcp pool DHCP213
network 192.168.213.0 255.255.255.0
default-router 192.168.213.200
dns-server 192.168.200.199

!
ip dhcp pool DHCP214
network 192.168.214.0 255.255.255.0
default-router 192.168.214.200
dns-server 192.168.200.199

!
ip dhcp pool DHCP209
network 192.168.209.0 255.255.255.0
default-router 192.168.209.200
dns-server 192.168.200.199
!
ip dhcp pool dhcp210
lease 48
!
ip dhcp pool dhcp211
lease 48
!
ip dhcp pool dhcp212
lease 48
!
ip dhcp pool dhcp213
lease 48
!
ip dhcp pool dhcp214
lease 48
!

!

Please do let me know if some more information is required.

Regards,

Eash

devils_advocate · ‎01-08-2015

Could just be an odd anomaly.

I would either delete and recreate the pool or reboot the switch.

eash · ‎02-18-2015

Dear Peter,

I made the changes as suggested. I moved the lease to uppercased dhcp pool and removed the lowercased ones.

My question inspite of it the lease ip address did not change and the exclude ip address shown is wrong.

Please see the below changes

router#ip dhcp remember
ip dhcp conflict resolution
ip dhcp excluded-address 192.168.210.1 192.168.210.31
ip dhcp excluded-address 192.168.210.160 192.168.210.254
ip dhcp excluded-address 192.168.211.1 192.168.211.31
ip dhcp excluded-address 192.168.211.160 192.168.211.254
ip dhcp excluded-address 192.168.212.1 192.168.212.31
ip dhcp excluded-address 192.168.212.160 192.168.212.254
ip dhcp excluded-address 192.168.213.1 192.168.213.31
ip dhcp excluded-address 192.168.213.160 192.168.213.254
ip dhcp excluded-address 192.168.214.1 192.168.214.31
ip dhcp excluded-address 192.168.214.160 192.168.214.254
ip dhcp excluded-address 192.168.209.1 192.168.209.31
ip dhcp excluded-address 192.168.209.160 192.168.209.254
!
ip dhcp pool DHCP210
   network 192.168.210.0 255.255.255.0
   default-router 192.168.210.200
   dns-server 172.16.141.13
   lease 2
!
ip dhcp pool DHCP211
   network 192.168.211.0 255.255.255.0
   default-router 192.168.211.200
   dns-server 172.16.141.13
   lease 2
!
ip dhcp pool DHCP212
   network 192.168.212.0 255.255.255.0
   default-router 192.168.212.200
   dns-server 172.16.141.13
   lease 2
!
ip dhcp pool DHCP213
   network 192.168.213.0 255.255.255.0
   default-router 192.168.213.200
   dns-server 172.16.141.13
   domain-name exedy.co.jp
   lease 2
!
ip dhcp pool DHCP214
   network 192.168.214.0 255.255.255.0
   default-router 192.168.214.200
   dns-server 172.16.141.13
   lease 2
!
ip dhcp pool DHCP209
   network 192.168.209.0 255.255.255.0
   default-router 192.168.209.200
   dns-server 172.16.141.13
   lease 2
!
router#sh ip dhcp pool

Pool DHCP210 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 4294967248
Excluded addresses             : 163
Remembered addresses           : 2
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.210.50       192.168.210.1    - 192.168.210.254   4294967248 / 163   / 254

Pool DHCP211 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 0
Excluded addresses             : 128
Remembered addresses           : 16
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.211.87       192.168.211.1    - 192.168.211.254   0     / 128   / 254

Pool DHCP212 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 2
Excluded addresses             : 128
Remembered addresses           : 29
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.212.70       192.168.212.1    - 192.168.212.254   2     / 128   / 254

Pool DHCP213 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 0
Excluded addresses             : 126
Remembered addresses           : 1
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.213.65       192.168.213.1    - 192.168.213.254   0     / 126   / 254

Pool DHCP214 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 0
Excluded addresses             : 126
Remembered addresses           : 0
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.214.1        192.168.214.1    - 192.168.214.254   0     / 126   / 254

Pool DHCP209 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 0
Excluded addresses             : 126
Remembered addresses           : 0
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.209.34       192.168.209.1    - 192.168.209.254   0     / 126   / 254

one more thing I get repeated dhcp-4_ping_conflict messages.

Request you suggestion.

Eash

eash · ‎02-27-2015

Hi peter,

As per your suggestion,

After removing all the duplicate DHCP pools in lowercase and enabling no ip dhcp logging the problem of clients not able to get IP address from DHCP got resolved to some extend.

But when I observed in the VLAN 210 after leased IP touches 110 no new clients are able to obtain IP address. Although the pool has 128 ip's address to lease.

Please let me know if there is any problem in my above DHCP configuration and when I issue clear ip dhcp binding * to reset and the sh ip dhcp pool of vlan 210 starts showing the weird leased ip's as below,

router#sh ip dhcp pool

Pool DHCP210 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 4294967248
Excluded addresses             : 163
Remembered addresses           : 2
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.210.50       192.168.210.1    - 192.168.210.254   4294967248 / 163   / 254

could adding ip helper-address in my L2 switch be of any help.

My network is follows,

Core (3750) === L2 (2960)== clients for each of the VLAN's.

Request your helpful inputs. This problem is really bugging me.

Eash

rakeshvelagala · ‎02-27-2015

Hi

router#sh ip dhcp pool

Pool DHCP210 :
Total addresses                : 254
Leased addresses               : 4294967248
Excluded addresses             : 163
Remembered addresses           : 2

Hi You have excluded 163. So leave you only atmost 254-163 around 90.

Thanks

eash · ‎02-28-2015

Hi Raksha,

The problem that I am facing is, in the VLAN 210 after leased IP touches 110 no new clients are able to obtain IP address from the DHCP. Although the pool has 128 IP's address to lease and the number of IP's excluded is 126 as can be seen in the config show earlier.

When I issue clear ip dhcp binding * to reset after that when I check sh ip dhcp pool I observe for vlan 210 it is showing weird leased and excluded IP's as below,

router#sh ip dhcp pool

Pool DHCP210 :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 4294967248
Excluded addresses             : 163
Remembered addresses           : 2
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased/Excluded/Total
192.168.210.50       192.168.210.1    - 192.168.210.254   4294967248 / 163   / 254

Request you valuable suggestion to resolve this problem.

Eash

eash · ‎03-01-2015

Dear All,

Any thoughts of what could be causing this problem.

I need your support to emergency situation.

Regards,

Eash

Peter Paluch · ‎01-08-2015

Eash,

I do not see anything suspicious except for one thing: You have two pools of the same name for each intended pool, one's name written out in uppercase, the other in lowercase. As the names of DHCP pools are case sensitive, you have in fact have two pools, one of them having all the addressing information, the second having only the lease time defined. I am sure this is not what you wanted.

Can you try correcting this by moving the lease 48 keyword to the uppercased DHCP pools, and then removing all duplicate DHCP pools having the lowercased name please? Perhaps this duplicity is what is confusing your IOS.

Best regards,
Peter