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New Member

Failed to get DHCP response on interface "Marking interface dirty"


i have WLC 5508 showing the below Logs , which prevent the users from connecting to the SSIDs , also its disconnecting the associted users

DHCP Socket Task: Jul 11 09:54:08.992: %SIM-3-DHCP_SERVER_NO_REPLY: sim_interface.c:1039 Failed to get DHCP response on interface 'interface-02'. Marking interface dirty.

*mmListen: Jul 11 09:54:08.638: %MM-3-INVALID_PKT_RECVD: mm_listen.c:7671 Received an invalid packet from Source member: source member unknown.


it shows 3 to 4 times durring 1 hour ,        

any idea about the problem , and what exactly Dirty interface means ??

Everyone's tags (5)
Cisco Employee

Re: Failed to get DHCP response on interface "Marking interface

looks like you could be using interface group.

(WLC) >show interface group detailed

Interface marked with * indicates DHCP dirty interface.

whenever the existing interface goes dirty does the client tries the next available interface for dhcp.

The idea of Interface Groups is that you can have a WLAN utilize multiple interfaces/VLANs/Subnets/DHCP Pools, either for load balancing. At its heart it is purely round robin or based on hash generated using mac address(it depends on the wlc code), but should a client connect in on a certain interface and not be able to complete the DHCP process we mark it as dirty for 30 minutes.  During those 30 minutes we basically remove that Interface from the Interface Group as it won't be selected for use.

New Member

Failed to get DHCP response on interface "Marking interface dirt

thanks for your help , i will give you some details about my network , it may help to figure out the problem exactly

i have 4 diffrent SSIDs each ssid have interface groub contain 25 interfaces , each SSID have different config. ,

dirty interface show up in two SSIDs , first one uses NAC for authin. and security ,second ssid use WEP authin .

the problem that dirty interface appear randomly in different interfaces ,

New Member

Hi guys,So what is the

Hi guys,

So what is the solution for this Issue? Kindly advice