Configure SNAT Pool custom SNMP MIB

Hello community,

I'm trying to monitor how many connections are in my SNAT pool to control that connection limits are not exceeded. My NMS is Zabbix.

In my scenario, I get "Current Connections" for each SNAT Pool using next snmp query:

 snmpwalk -v2c -c public localhost F5-BIGIP-LOCAL-MIB::ltmSnatPoolStatServerCurConns
F5-BIGIP-LOCAL-MIB::ltmSnatPoolStatServerCurConns."/Common/SNAT_test" = Gauge32: 513
F5-BIGIP-LOCAL-MIB::ltmSnatPoolStatServerCurConns."/Common/SNAT_pub" = Gauge32: 21444
After this, I would like to trigger an alert (in Zabbix) when those Current Connections exceed 80% of the SNAT Pool capacity (to include a new IP in the pool in that case). We estimate the SNAT Pool capacity in 65k connections for each IP in the pool. A query with next structure would be perfect to set this trigger:
 
 snmpwalk -v2c -c public localhost F5-BIGIP-LOCAL-MIB::XXXXXXXXXXXXXXXX
F5-BIGIP-LOCAL-MIB::XXXXXXXXXXXXXXXX."/Common/SNAT_test" = INTEGER: 2
F5-BIGIP-LOCAL-MIB::XXXXXXXXXXXXXXXX."/Common/SNAT_pub" = INTEGER: 7
(Note that the result should show how many IPs are configured in each pool).
 
I didn't find anything like this in MIB, so I decided to create a custom MIB, but just a few of structures are available (INT, STRING, GAUGE, and COUNTER), and Lists are not included. So I guess this is not possible using this way... 😞
 
Any idea to solve this? (create "custom_mib.tcl" dynamically with a crontab is not an option).
 
I have tried if lists of strings are permited using next code:
 
/config/snmp/custom_mib.tcl
 
register_mib ".2" testmib string
proc testmib {}
set result [split "Hello world" " "]
return $result
But after SNMP query, no string splitting was performed: