snmptd probe on Linux binding port 162 is not processing any traps

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)
• CA Unified Infrastructure Management On-Premise (Nimsoft / UIM)
• CA Unified Infrastructure Management SaaS (Nimsoft / UIM)

Issue/Introduction

The snmptd probe installed on a Linux server is not processing any traps. A tcpdump shows that the traps are arriving.  There are no firewall rules blocking the port and "netstat -anp" does not show the snmptd process binding to port 162. In this environment, the snmptd process is owned by a non-root user.

Environment

• UIM server: any supported version
• snmptd:  any version
• OS:  any UNIX/Linux system the snmptd probe is certified on

Cause

• The snmptd probe listens for incoming traps on port 162. If the probe's process is not owned by root, the probe will not work. 
• On UNIX/Linux systems, any process that is expected to listen on a particular port needs to have the listening port configured to a port value above 1024.  Since the snmptd probe listens on port 162, it will not work in a 'non-root' context.

Resolution

Either change the port that the snmp traps are sent out on and configure the snmptd probe to retrieve them from that port, or change the UIM ownership to root.