Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

Wireless dot1x authenticated but no IPv4 DHCP assignment

Hi all, facing some issue on wireless not getting IP from the external DHCP server.

 

01. Problem statement

After authentication success, client PC cannot get IP from DHCP server.

 

This is the error log found at the WLC

*RRM-MGR-2_4-GRP: May 21 15:23:02.643: #LOG-3-Q_IND: dhcp_proxy.c:3944 Received a DHCP packet sent by the controller itself possible network loop![...It occurred 3 times.!]

*DHCP Socket Task: May 21 15:23:02.171: #DHCP-3-DHCP_PKT_LOOPED: dhcp_proxy.c:3944 Received a DHCP packet sent by the controller itself possible network loop!

*DHCP Socket Task: May 21 15:22:47.140: #DHCP-3-DHCP_PKT_LOOPED: dhcp_proxy.c:3944 Received a DHCP packet sent by the controller itself possible network loop!

*DHCP Socket Task: May 21 15:22:43.009: #DHCP-3-DHCP_PKT_LOOPED: dhcp_proxy.c:3944 Received a DHCP packet sent by the controller itself possible network loop!

*RRM-MGR-5_0-GRP: May 21 15:22:04.188: #LOG-3-Q_IND: acl.c:371 Unable to find an ACL by name ""

 

 

02. Troubleshooting effort and finding

There's 2 SSID create on the WLC, with different VLAN on each.

When connecting to the first SSID, it's successfully authenticate and able to get IP from the DHCP

 

When disconnect the client PC from first SSID, and connecting to the second SSID, from the client detail it is showing the connection is associated, no IP assigned, and policy manager state is "DHCP_REQD"

 

There is no IP lease at DHCP server (using window server 2008 as external DHCP, because virtual WLC is not support hosting internal DHCP server)

 

 

03. Existing Cisco device config and infrastructure setup

WLC version     : virtual WLC 7.6.100.0

client PC         :  window 7

 

Any suggestion and idea on this? 

 

million thanks in advance

 

4 REPLIES
New Member

Hi,

Hi, Most possible cause behind the issue is , dhcp timeout during dot1x process. You can check the dot1x timeout , reduce the default values so that dhcp will not fail during dot1x process. Hope this helps. Virender.
VIP Purple

Hi,Try disabling dhcp proxy (

Hi,

Try disabling dhcp proxy ( config dhcp proxy disable ) & check if this helps. If still not help then you must be hitting this Bug:

https://tools.cisco.com/bugsearch/bug/CSCuj14843

or try to contact TAC.

Regards

Dont forget to rate helpful posts

Bronze

Hi,1. As per my understanding

Hi,

1. As per my understanding you have not properly configure the DHCP proxy, recheck you configuration and commands.

2.   DHCP option 82 is a king of enhancement specifically employed for distributed DHCP/relay enviornments, using this option relays insert specific information to the request, for to get an idea of clients physical point of attachment or first interaction to the network.

   For understanding DHCP option 82 check the below blog.

   http://blog.ine.com/2009/07/22/understanding-dhcp-option-82/

New Member

Hi Yongkhang,You can simplify

Hi Yongkhang,

You can simplify your problem by doing the following:

  1. Create new WLAN using WPA2-PSK for test purposes only.  Assign this to SSID1 VLAN and check DHCP services.  Then re-assign this test SSID to SSID2 VLAN and check DHCP services.
  2. Once DHCP is confirmed then include the 802.1X setup and potentially enable AAA Override if that's what you want to achieve.

Also ensure you have FAST SSID CHANGE enabled when you are flicking between different SSIDs on the same WLC-AP.  First impression, I thought this was the issue.

Best of luck.

HTH

Adrian

308
Views
0
Helpful
4
Replies
CreatePlease to create content