02-18-2014 07:45 AM - edited 07-05-2021 12:13 AM
Customer is using a 4400 WLC.
He has a management tool that works using the SNMP logs from the controller, he can ping the controller using this management tool, but when he sends SNMP requests from the management tool the WLC doesn't reply.The SNMP server IP address is 192.168.122.11 and the WLC's IP address is 10.20.1.31.
I have the following debug taken from the switchport where the WLC is connected.
'debug snmp agent' shows some interesting messages that confirms that the WLC is not sending a packet back.Cisco Controller) >debug snmp agent enable (Cisco Controller) >*SNMPTask: Feb 06 14:38:44.616: SNMPD: Packet from: 192.168.122.11:2509, in_packet_len = 59 *SNMPTask: Feb 06 14:38:44.616: SNMPD: Failed to build in SnmpMessage. 1145 Debug Messages have been dropped*SNMPTask: Feb 06 14:38:44.616: SNMPD: *NOT* sending out packet, out_packet_len = 0 *SNMPTask: Feb 06 14:38:47.621: SNMPD: Packet from: 192.168.122.11:2509, in_packet_len = 59 *SNMPTask: Feb 06 14:38:47.621: SNMPD: Failed to build in SnmpMessage. *SNMPTask: Feb 06 14:38:47.621: SNMPD: *NOT* sending out packet, out_packet_len = 0 *SNMPTask: Feb 06 14:38:50.652: SNMPD: Packet from: 192.168.122.11:2509, in_packet_len = 59 *SNMPTask: Feb 06 14:38:50.652: SNMPD: Failed to build in SnmpMessage. *SNMPTask: Feb 06 14:38:50.652: SNMPD: *NOT* sending out packet, out_packet_len = 0 *SNMPTask: Feb 06 14:38:53.684: SNMPD: Packet from: 192.168.122.11:2509, in_packet_len = 50 *SNMPTask: Feb 06 14:38:53.684: SNMPD: Failed to build in SnmpMessage. *SNMPTask: Feb 06 14:38:53.684: SNMPD: *NOT* sending out packet, out_packet_len = 0 *SNMPTask: Feb 06 14:38:56.715: SNMPD: Packet from: 192.168.122.11:2509, in_packet_len = 50 *SNMPTask: Feb 06 14:38:56.715: SNMPD: Failed to build in SnmpMessage. *SNMPTask: Feb 06 14:38:56.715: SNMPD: *NOT* sending out packet, out_packet_len = 0 *SNMPTask: Feb 06 14:38:59.747: SNMPD: Packet from: 192.168.122.11:2509, in_packet_len = 50 *SNMPTask: Feb 06 14:38:59.747: SNMPD: Failed to build in SnmpMessage. *SNMPTask: Feb 06 14:38:59.747: SNMPD: *NOT* sending out packet, out_packet_len = 0
I have also a packet capture taken from the same switchport, I attach it here.
What could be the reason for not responding?
Solved! Go to Solution.
02-18-2014 08:01 AM
You need to add the management tool in the WLC as a trap reciever.
Thanks,
Scott
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02-18-2014 08:01 AM
You need to add the management tool in the WLC as a trap reciever.
Thanks,
Scott
*****Help out other by using the rating system and marking answered questions as "Answered"*****
02-18-2014 08:36 AM
Hi Scott,
Thank you for the steps, I will implement it and then let you know if it solved the issue.
Have a nice day!
02-18-2014 12:21 PM
No problem...
Thanks,
Scott
*****Help out other by using the rating system and marking answered questions as "Answered"*****
03-12-2014 11:04 AM
Hi Scott,
It worked, but we needed to use SNMP v2 to make it!
Thank you so much.
10-21-2014 05:15 PM
I disagree that this is a solution. It is a workaround to a bug or issue, but I have another WLC of the same model that can use SNMPv3 to connect to Prime Infrastructure and one that is having exactly this same issue.
06-13-2018 09:50 AM
02-18-2014 01:21 PM
Robin,
Just to note.... This is the same setting when your adding WCS/NCS or Prime to WLC. Without this being set, snmp will not work. Take a look at other installs that use WCS/NCS or Prime.
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