Hello everyone,
I'm monitoring SonicWall VPN sensors using the "Policy Name" as the identification method and I just got curious how PRTG does this monitoring.
First, the OID that SonicWall uses to show the Active Tunnels is: 1.3.6.1.4.1.8741.1.3.2.1.1.1.14.X
Where "X" is the unique ID of the active tunnel. Once the connection of this tunnel is lost or reconnected, this ID changes. And the thing is, how does PRTG do to keep the sensor UP even if the ID has changed? I know that maybe it compares the strings results from this OID. And if the string is the same, the sensor keeps up...
Is there some way to get the "source code" of this sensor? To see how it does to compare the checks in order to keep the sensor up? I'm curious because I would like to create a windows-based script to monitor a VPN that it not sonicwall but uses the same thing about "changing id on every reconnection".
Thanks!
Hello there,
Here's what I can say: 1.3.6.1.4.1.8741.1.3.2.1.1.1.14.index delivers the name of the security policy as a string, which is what you chose for identification. As far as I know the trick here is that the sensor doesn't save the index permanently when created. Instead the required table will be examined with each scan to find the related policy name first and go from there then pulling all the other related metrics for this security name and its current index.
It's basically the same principle as with the SNMP Custom Table Sensor, where you configure it to pull data from a certain table and need to define which table entry to use for identification to keep things together (which of course should be a unique identifier/name that is not expected to change all the time).
Kind regards,
Erhard
Jul, 2017 - Permalink