DHCP not releasing IP Address + Cisco IOS

[vinu4u4ever]

Hello, there.

I created a DHCP pool in our Cisco router 887 but unfortunately it is not releasing the IPs.

I'm new to Cisco so please ignore if it is a silly query.

Attached is the configuration taken from the Router.

[Mark Malone]

Your configs ok , have you tried rebooting the router incase the service is locked or its some odd bug ?

Your configs ok , have you tried rebooting the router incase the service is locked or its some odd bug ?



try clear ip dhcp bindings * then reload and see if the issue still persists

[vinu4u4ever]

Hello, Mark.

Thank you for prompt reply.

I tried reloading our router but no luck..

Had a check on DHCP binding,,, nothing is listed but still I ran the clear command unfortunately the issue still presists. 

Thanks for helping.

[Mark Malone]

Just so we know what your seeing how are you telling its not releasing the address ?
When you check the show ip dhcp pool does it give out the addresses one by one after each other
Is there anything strange in the logs for DHCP , what version of software are you on

[vinu4u4ever]

Hello, Mark.

Here is the result:

patchi01#show ip dhcp bind
patchi01#show ip dhcp binding
Bindings from all pools not associated with VRF:
IP address Client-ID/ Lease expiration Type
Hardware address/
User name
patchi01#show ip dhcp po
patchi01#show ip dhcp pool

Pool LAN :
Utilization mark (high/low) : 100 / 0
Subnet size (first/next) : 0 / 0
Total addresses : 254
Leased addresses : 0
Pending event : none
1 subnet is currently in the pool :
Current index IP address range Leased addresses
192.168.1.1 192.168.1.1 - 192.168.1.254 0
patchi01#

[Mark Malone]

Ok so that shows no addresses been given out in the pool , is the problem you cant get an address from the pool on the router or you get the address and then it wont release it ?

[Mark Malone]

You could try command debug dhcp detail and see whats happening on the router when the client is trying to obtain an address or in case its a software bug try a newer version ios from the Cisco website , make sure ip dhcp service is enabled in global config , you can see what services are on by default with sh run all

[vinu4u4ever]

Hello, Mark.

I'm sorry for the delay in response.

The thing is I'm not getting any ip address in the client PC.

[Predrag Jovic]

2 details:

What is output from commands

sh interface status

sh ip int brief

Having MSS = MTU size obviously is not good (also is unrelated to your issue, but should be corrected).

MSS = MTU - 40

interface Vlan2
 ip mtu 1412
 ip tcp adjust-mss 1412

[vinu4u4ever]

Hello, Predrag.

Here are the result as per your request.

[vinu4u4ever]

Thank you for your suggestion regarding MSS & MTU.

I'll update it acoordingly.

IF you don't mind, can u explain me regarding this MSS & MTU?

[vinu4u4ever]

[Austin Sabio]

Try 'no service dhcp' then use 'service dhcp' to reenable dhcp and see if that helps. 

Good luck!

-Austin 

[vinu4u4ever]

Hello, Austin.

Thank you for the resply. Tried your solution but unfortunately the result was same.

[Austin Sabio]

At this point. It has to be a bug (maybe related to CSCeb36127 and CSCuh95199) won't say for sure without checking the logs and getting debug dhcp detail result. I would recommend to upgrade the code and this has to fix it. 

Your current version is 

c880data-universalk9-mz.151-4.M.bin

25-MAR-2011

Recommended two are available:

c800-universalk9-mz.SPA.154-3.M8.bin

31-JUL-2017

c800-universalk9-mz.SPA.153-3.M10.bin

31-JUL-2017

I hope this helps. Good luck! 

-Austin