If your NetMRI seems to be taking a long time to discover the devices on your network or has only discovered a small number of devices here are some things to check:

1) Check to make sure that the list of CIDR Blocks configured  on the "Settings">"CIDR Blocks" page is complete and covers all of the devices you want to discover.

NetMRI will not discover any devices that are not part of a configured CIDR Block.

2) Are any of the CIDR blocks smaller than a /20 (i.e. /24)? If so, Reduce some CIDR blocks and add a few /32 CIDR blocks for a few "key routers" in your network that NetMRI will be able to access via SNMP. NetMRI relies on ARP and routing tables to identify potential devices for discovery so adding a few routers which contain large ARP and Route tables as /32 CIDR Blocks can expedite the discovery process

3) Was NetMRI configured on a crossover cable and rebooted on the crossover cable then switched to the actual network after the reboot? If so, NetMRI may have already performed its initial traceroutes.  You can click the "Reset Discovery Counters" button on the Settings ->CIDR Blocks page to force the traceroutes again.

4) Are the SNMP community strings provided correct? Check for common mistakes such as replacing a “1” with the letter “l” and vice-versa.

You can review the configured list and make changes/corrections via the GUI: "Settings">"Settings">"SNMP Collector".
On this same screen make sure the "SNMP Collector" is "Enabled".

5) Are the Devices that are not being discovered pingable via the NetMRI

Use the NetMRI Ping Tool available via the GUI to check a few devices:
"Tools">"Network Tools">"Ping/Traceroute

6) Are there access lists or firewalls that may be preventing NetMRI from SNMP polling certain devices or portions of the network?

Use the NetMRI SNMP Walk Tool (Available via the GUI) "Tools">"Device Tools">"SNMP Walk Tool" see if you are able to communicate with a device you believe that NetMRI should have discovered.

On the SNMP Walk Tool screen enter the "IP Address", "Community String"  and "Root OID" (For Root OID just enter "System")

If you do not receive SNMP response from the device and you believe the community string you entered is correct then check the device itself to see if perhaps an ACL is configured that may be blocking access.

It's also possible that an ACL configured on a Firewall or Router in the path to the device is blocking the access so check that as well.

7) The NetMRI Discovery Status Page provides a good overview as to how Discovery is progressing.

"Results">"Network">"Discovery Status"

This table provides a list of all devices that NetMRI has attempted to discover so far. It may include a lot of devices NetMRI won't be able to access via SNMP (ie workstations, servers,etc) so "sort" it via the "Device Type" column (you can just click on the column heading) and then review the switches, routers, etc to see if SNMP Access is "failed" for some reason.

8) As a final troubleshooting step perform a "Discovery Diagnostic" for a few devices that you believe NetMRI should have been able to discover and send the result to support@netcordia.com for review.

- Via the GUI: "Tools">"Device Tools">"Discovery Diag"
- On this screen enter the IP Address and SNMP Community String. Click "On" for  the "Force Tests" option
- Click OK
- Once the diagnostic is complete click the Blue "Text" button in the left hand corner of the screen to save the resulting file locally
- Send this file to support@netcordia.com