Find Version Number (numberic)

[brandilton]

I'm trying to setup an SNMP alert to let me know when a device isn't running the latest version…  I've found OID .1.3.6.1.2.1.1.1.0 which tells me something like:

pfSense pfsense.xyx.com 2.1.5-RELEASE pfSense FreeBSD 8.3-RELEASE-p16 i386

but is there another OID that would just report the numeric "2.1.5" so i could create an easy alert that goes something like:

If OID <= 2.1.5 email updatemyfirmware@support.com