Orion Network discovery fails due to limited time to scan subnet

3/20/2020 12:07 AM

10/29/2021 1:29 AM

Customer creates a network discovery on a subnet but it consistently fails the error is related to timeout issues on the discovery

Orion Platform

Understanding CIDR Subnet Mask Notation

pfSense® firewalls use CIDR (Classless Inter-Domain Routing) notation rather than the common subnet mask 255.x.x.x when configuring addresses and networks. Refer to the CIDR Subnet Table to find the CIDR equivalent of a decimal subnet mask.

CIDR table:





The problem happens when the configured discovery timeout is not enough to perform the job.
As an example, /21 has a total of 2048 IP addresses. NPM Network discovery time out is set at 60 mins by default, SNMP community string attempt is at 10 seconds, and SNMP retry is at 10 seconds. 60 minutes is not enough time to complete the job.

Adjust the Network Discovery Timeout value

Get the CIDR that is configured on the subnet and then check how many credentials are being attempted to poll the devices. check each credential next attempt time. Calculate how many minutes can be used to complete the job.

Still basing on the example:

In a perfect world, it would take 358 to complete the job. However, for SNMP attempt failure, the job will roll 10 seconds again to try the next SNMP community string for one IP address. Use trial and error and place an acceptable time out for the job with reserved amount of time for unexpected/expected retry on WMI and SNMP credentials polling attempt. 

Here is how you edit modify the network discovery timeout:
1. Click on Settings > Network Discovery

2. From Network Sonar Discovery page, choose a discovery profile and then click on Edit

3. Go through the Network Sonar Wizard until you reach Discovery Settings. Make changes on Retries and Timeouts then click on the Next button:

4. Select Yes run discovery now, or No do not run now