Hello, I spent some time on the following issue so wanted to pass this along in case someone else saw weird stuff from their Sonicwall device. The attached shows the Routing Table where the 192.168.10.0 route is not /24, but is reported as such.
Symptoms
In the resource "Routing Table", the CIDR may not be accurate for the Sonicwall NSA 3500. For example, the CIDR may always be reported as 24 regardless of variable length subnet masking (VLSM.)
Cause
While Sonicwall devices may respond to standards based MIBs, they only support custom MIBs published through www.mysonicwall.com . Specifically, the Sonicwall NSA 3500 may provide incorrect responses to requests for OID 1.3.6.1.2.1.4.21.1.11 (ipRouteMask)
Workaround
Remove the resource "Routing Table" from NPM for the Sonicwall NSA 3500.