APs unable to receive IP address from DHCP (core 6500 series switch)

[Faisal Shabbir]

Dear Friends,

a week ago I had stable wireless network APs were getting IPS from 6500 series switch (DHCP) but unfortunately some WISM got rebooted and now APs are unable to receive IP address from Core 6500 DHCP, to cater this issue  I have another DHCP server configured on windows 2008  i created another subnet and and put APs in that vlan now all APs are are successfully receiving IPS from windows DHCP server I don't know why APs are not able to receive IPs from core 6500 series DHCP.

please advice

Thanks

Faysal

[Stephen Rodriguez]

The WiSM rebooting is most likely a red-herring as the AP would need to get it's IP prior to contacting the WLC.

If it was just some AP, was there a geographical similarity? i.e. same switch/path to the 6500.

HTH,
Steve

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[Faisal Shabbir]

Thanks for Reply Stephen

i have two 6500 core switches each has one WISM and and each wism has two controllers i have almost 250 Aps and not a single AP is getting IP from core switch

[Stephen Rodriguez · Accepted solution]

Did the VLAN get removed somewhere?  I've seen where VTP pruning pulled a VLAN when an upstream switch was disconnected.  So possibly, if the AP VLAN was trunked to the WiSM and the WiSM went away pruning could have kicked in.

If you plug a laptop into the VLAN, does it get an IP address from the 6500?

HTH,
Steve

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[Faisal Shabbir]

You are right its trunked with WISM and vlan is in allowed list when i connect my laptop i dont receive any IP however the controllers are configured with static IPS from the same subnet and ping able from core switch .

[Faisal Shabbir]

when i connect AP into same vlan Aps are getting this message:

Mar 1 00:25:38.035: %CAPWAP-3-ERRORLOG: Not sending discovery request AP does not have an Ip !!

*Mar 1 00:25:38.035: %CAPWAP-5-DHCP_RENEW: Could not discover WLC using DHCP IP. Renewing DHCP IP.

*Mar 1 00:25:48.035: %CAPWAP-3-ERRORLOG: Not sending discovery request AP does not have an Ip !!

*Mar 1 00:25:58.035: %CAPWAP-3-ERRORLOG: Not sending discovery request AP does not have an Ip !!

*Mar 1 00:26:08.035: %CAPWAP-3-ERRORLOG: Not sending discovery request AP does not have an Ip !!

*Mar 1 00:26:18.035: %CAPWAP-3-ERRORLOG: Not sending discovery request AP does not have an Ip !!

Not in Bound state.

[Stephen Rodriguez · Accepted solution]

ok, so that sounds more like a DHCP issue with the 6500, can you do a show ip binding?  make sure the leases aren't exhausted.

I think you can also do a debug dhcp on the sup and get some information out of there as well.

HTH,
Steve

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[Faisal Shabbir]

it seems to be a DHCP issue Stephen i am away from network right now  but when i isues dhow dhcp server command lease, binding, request everthing was ZERO ,

[Faisal Shabbir]

is there any settings on WLAN controllers to get an IP for APs from 6500 switch ???

[Stephen Rodriguez · Accepted solution]

No there is not.  The AP will do it's DHCP request when it first comes up, which is before it tries to talk to the WLC.

HTH,
Steve

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[Faisal Shabbir]

i am not a wireless expert just managing the network what else could be the reason that DHCP is not working??

[Stephen Rodriguez]

nothing off the top of my head, but at this point it's not a 'wireless' issue perse, but a network/dhcp issue.

HTH,
Steve

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[George Stefanick]

Can you post the config of your 6500 ?

__________________________________________________________________________________________
"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
__________________________________________________________________________________________
‎"I'm in a serious relationship with my Wi-Fi. You could say we have a connection."

[Faisal Shabbir]

Thanks george for stepping up here is DHCP config

!

!

ip dhcp excluded-address 10.10.30.1 10.10.30.20

ip dhcp excluded-address 10.10.8.1 10.10.8.10

ip dhcp excluded-address 192.168.10.1 192.168.10.5

ip dhcp excluded-address 10.9.20.1 10.9.20.30

!

ip dhcp pool vlan_30

network 10.10.30.0 255.255.254.0

default-router 10.10.30.1

option 60 ascii """"""""""""""""""""""""CiscoAPc1250""""""""""""""""""""""""

option 43 hex f110.0a0a.1e0b.0a0a.1e0d.0a0a.1e0f.0a0a.1e11

dns-server 10.10.2.11

lease infinite

!

ip dhcp pool WiSM1_SP

network 192.168.10.0 255.255.255.248

default-router 192.168.10.1

!

[Faisal Shabbir]

if you need any other info please let me now