Network Topology
Customer ACs are distributed in different cities, headquarters and branch network
Problem Description
A site needs to read the number of wireless clients connected under each ssid through snmp, and the relevant mib nodes are 1.3.6.1.4.1.25506.2.75.2.1.7.1.5. After testing, we found that we can get the relevant client number information by reading the headquarters AC, but the number of clients returned by the branch node is 0, and there are actually clients connected under the ssid. The AC model is WX3540H, the headquarters AC uses version 5441P02, and the branch AC uses version 5439P03.
Process Analysis
First check the snmp-related configuration of the headquarters and the branch, no abnormality is found, and the group name used by the headquarters and the branch is the same.
snmp-agent
snmp-agent local-engineid xxx
snmp-agent community read xxx
snmp-agent sys-info version v2c
snmp-agent
snmp-agent xxx
snmp-agent community read xxx
snmp-agent sys-info version v2c v3
The debugging snmp agent packet send/debugging snmp agent packet receive information is then collected on the headquarters and branch ACs respectively.
The debug information of the headquarters AC is as follows
Packet received from 10.X.X.X via UDP
*Aug 4 10:01:44:993 2021 WX3540[5F] SNMP/7/PACKET.
Get request
Request ID: 919018455
Error status: 0
Error index: 0
*Aug 4 10:01:44:994 2021 WX3540[5F] SNMP/7/VBLIST.
hh3cDot11APAssocStaNum.1.
*Aug 4 10:01:44:995 2021 WX3540[5F] SNMP/7/PACKET.
Response
Request ID: 919018455
Error status: 0
Error index: 0
*Aug 4 10:01:44:995 2021 WX3540[5F] SNMP/7/VBLIST.
hh3cDot11APAssocStaNum.1: 4686
*Aug 4 10:01:44:996 2021 WX3540[5F] SNMP/7/PACKET_DES.
Packet sent to 10.X.X.X via UDP
It can be found that the debug information of the headquarters AC records the whole process from receiving the node information requested by the snmp server to replying to the server with the relevant node parameter 4686, and there are 4686 terminals online under this ssid.
The debug information of the branch AC:
Packet received from 10.X.X.X via UDP
*Jul 29 15:11:44:972 2021 AC SNMP/7/PACKET.
Get request
Request ID: 18505931
Error status: 0
Error index: 0
*Jul 29 15:11:44:972 2021 AC SNMP/7/VBLIST.
hh3cDot11APAssocStaNum.1.
*Jul 29 15:11:44:973 2021 AC SNMP/7/PACKET.
Response
Request ID: 18505931
Error status: 0
Error index: 0
*Jul 29 15:11:44:974 2021 AC SNMP/7/VBLIST.
hh3cDot11APAssocStaNum.1: 0
*Jul 29 15:11:44:974 2021 AC SNMP/7/PACKET_DES.
Packet sent to 10.13.62.253 via UDP
Similar debug message as HQ, but the node value returned to the snmp server is 0, but there are a large number of endpoints online under this ssid viewed on the AC.
The debug information of the headquarters and the division AC, first of all, we can confirm that there is no problem with the connectivity between the snmp server and the division AC, and exclude the possibility that the message may be lost in the intermediate link, then we have to continue to analyze why there is obviously a terminal online under a certain ssid of the division AC but the return value is 0. Although the versions used by the headquarters and the division AC are different, but the version span is relatively small, and we have confirmed that We can exclude the reason of version difference because no changes have been made to snmp between these two versions.
Then after excluding the influence of intermediate links and version software problems, we still suspect the basic configuration problem. Combined with the query mib node for the number of wireless clients connected under the wireless service template, it occurred to me to check whether there were differences in the configuration of the wireless service template between the headquarters AC and the branch AC.
Headquarters AC service template configuration:
wlan service-template 1x
ssid xxx
vlan 2000
client forwarding-location ap
service-template enable
Branch AC service template configuration:
wlan service-template gwireless
ssid Gwireless a
vlan 99
association-location ap
client forwarding-location ap
client-security authentication-location ap
service-template enable
Compare the configuration of the wireless service template of the headquarters AC with that of the branch AC, we find that the configuration of the branch AC has more wireless client association points and authentication points in the ap: client association-location ap, client-security authentication-location ap, after canceling these two configurations After removing these two configurations, the snmp server can read the number of wireless clients connected under the division AC wireless service template.
Solution
Due to the configuration of the client association and authentication points on ap, the snmp server reads the relevant mib node return value as 0:
client association-location ap
client-security authentication-location ap
The snmp server can read the number of connected wireless clients under the wireless service template normally after the relevant configuration is removed on site