In addition to monitoring SNMP enabled devices located inside of your network Nectus can be configured to monitor ICMP reachibility of any external IP address by adding it to a list of “IP Monitors” First you need to define IP Monitor Group name where IP address will be added to: Make sure that “Monitoring” flag […]
For each router or switch found during discovery Nectus has to select one interface that will be used as a primary monitoring interface for basic reachibility checks, destination for SNMP queries etc.. Here is the selection order logic that implemented in Nectus Discovery Service: Select Interface that has assigned IP address associated with current DNS […]
To exclude specific subnet from Network Discovery add it to “Excluded subnets” list in “Settings -> Network Discovery Settings” This will exclude this subnets from ICMP scan phase and subsequently prevent live devices in this subnets from being queried via SNMP.
By default when you create a GRE tunnel (tunnel-ip1) on ASR9K routers it gets assigned default Bandwidth value of 8Kbps which usually causes utilization monitoring confusion as Tunnel can carry as much traffic as its hardware parent interface where tunnel is anchored to. You would see utilization values as high a 10,000% percent with default Bandwidth […]
During network discovery phase Nectus collects S/N for each device that responds to basic SNMP queries. One of the problem with Cisco Devices is that different platforms uses different OID to store S/N. Following OIDs are being used for Cisco: .1.3.6.1.2.1.47.1.1.1.1.11.1 .1.3.6.1.2.1.47.1.1.1.1.11.2 .1.3.6.1.2.1.47.1.1.1.1.11.10 .1.3.6.1.2.1.47.1.1.1.1.11.22 .1.3.6.1.2.1.47.1.1.1.1.11.1001 .1.3.6.1.2.1.47.1.1.1.1.11.24555730 .1.3.6.1.4.1.14179.1.1.1.4.0 .1.3.6.1.4.1.2467.1.34.4.0 .1.3.6.1.4.1.437.1.1.3.1.22.0 .1.3.6.1.4.1.9.20.1.1.1.1.3.0.1.3.6.1.4.1.7505.1.1.1.0 .1.3.6.1.4.1.9.6.1.101.53.14.1.5.1 .1.3.6.1.4.1.9.9.92.1.1.1.2.1 .1.3.6.1.4.1.9.3.6.3.0 .1.3.6.1.4.1.3076.2.1.2.22.1.63.0 .1.3.6.1.4.1.9.5.1.2.19.0 […]
Just run into a IOS-XR bug with running SNMP v3 with AES-128 cipher (as well as AES-192 and AES-256) on ASR 9000 Routers running 5.3.4 Code. Apparently Cisco BUG ID CSCvd35831. Fixed in 6.2.xx code. Upgrading ASR9K is fun that can take 4-5 hours per box but having SNMP communications secure is more important. Consider upgrading. […]
Sometimes specific device categories (UPS units, Printers etc) must be excluded from network discovery due to their low importance from the Network Monitoring prospective or due to security concerns or because of their impact on Nectus processing load. This can be achieved with OID ignore list. For example we want to prevent all Xerox ApeosPort Series […]
To obtain list of ifIndex values for all interfaces for given device SNMP polling agent has to send SNMP GET BULK request for the following OID: .1.3.6.1.2.1.2.2.1.1 Response Example: ‘.1.3.6.1.2.1.2.2.1.1.1’ => “1” ‘.1.3.6.1.2.1.2.2.1.1.2’ => “2” ‘.1.3.6.1.2.1.2.2.1.1.3’ => “3” ‘.1.3.6.1.2.1.2.2.1.1.4’ => “4” ‘.1.3.6.1.2.1.2.2.1.1.5’ => “5” ‘.1.3.6.1.2.1.2.2.1.1.6’ => “6” ‘.1.3.6.1.2.1.2.2.1.1.7’ => “7” ‘.1.3.6.1.2.1.2.2.1.1.8’ => “8” ‘.1.3.6.1.2.1.2.2.1.1.9’ => […]
This short video shows basic steps to generate site level network topology
Nectus Datasheet Medium
IOS-XR SNMP v3 configuration example for username “user_des” snmp-server group admins v3 priv snmp-server user user-des admins v3 auth md5 “authpass” priv des56 “privpass” SystemOwner this configuration will use MD5 hash for authentication and DES cipher (DES56) for encryption. IOS-XR (as of 5.3.4 code) also supports 3DES – 168 bit 3DES algorithm for […]
During Nectus installation user can define up to 10 IPv4 subnets that will be used as initial seed subnets for ICMP scan. Immediately after Installation is completed Nectus starts ICMP scan of provided subnets and builds a list of live IP addresses that responded to Ping.
When Nectus discovers a new device it uses its SNMP sysObjectID (1.3.6.1.2.1.1.2) value to classify device by manufacturer, by major platform category and by model number. For example sysObjectID value of 1.3.6.1.4.1.9.1.1018 Defined as: Manufacturer Value: Cisco Systems (9) Major Category: Cisco ASR 9000 Aggregation Services Routers Model: Cisco ASR 9006 Routers
What is the first question you ask when you start a new network project or start a new job as a network engineer?”: – Can I see your network diagram? Lucky you if you get it right away and in the “right” format (Visio?) but in my past I remember places where it took me […]