Enfore the IS-IS NET using a script-based configuration rule

Let's assume you want to enforce the configured IS-IS NET address on your IOS and IOS-XR routers to be derivated from the name of the router. Example:

function check(device) { // Get the type of device and ensure it starts with IOS, otherwise the script doesn't apply var type = device.get('type'); if (type.match(/Cisco IOS.*/)) { var name = device.get('name'); // Get the final number in the device name var id = name.match(/.*?([0-9]+)/); if (!id) { return { result: NOTAPPLICABLE, comment: "Does not apply to this hostname" }; } // Transform the number into a NET address (hex) id = parseInt(id[1]); id = id.toString(16).toLowerCase(); var net = ""; for (i = 0; i < 4 - id.length; i++) { net += "0"; } net += id; net = "49." + net + ".0000.0000." + net + ".00"; // Get the config (configuration for XR, runningConfig otherwise) var config = device.get('configuration'); if (!config) config = device.get('runningConfig'); // Find the IS-IS section var isis = device.findSections(config, /^router isis .*/); if (isis.length === 0) { return { result: NONCONFORMING, comment: "No IS-IS block" }; } isis = isis[0].config; // Get the configured NET address var cNet = isis.match(/^ net ([0-9a-f\.]+)/); if (!cNet) { return { result: NONCONFORMING, comment: "No NET configured" }; } cNet = cNet[1]; // Compare the computed and the configured NET addresses if (cNet === net) { return CONFORMING; } else { return { result: NONCONFORMING, comment: "Configured NET " + cNet + ", should be " + net }; } } return NOTAPPLICABLE; }

Add this as a Javascript-based compliance rule to Netshot, and now on your devices will be flagged if they don't respect the proper NET address format.