Not receiving traps to Spectrum, but they show in tcpdump/packet trace

Products

• Spectrum
• Network Observability

Issue/Introduction

We are developing Southbound Gateway integration with a third party SNMP trap sender. Confirmed the traps are landing on the Linux server via tcpdump on port 162, but we are not seeing the same traps processed on the VNM model within Spectrum. 

Environment

Component : Spectrum Core / SpectroSERVER

Linux OS

Cause

- iptables on the Linux OS are blocking traffic on port 162

- the kernel sends traffic to the tcpdump before hitting iptables firewall, so traps will show in tcpdump but are still technically blocked by the internal firewall

 

 

Resolution

To disable internal firewall and iptables, log in as root and run this command:  

$ systemctl stop firewalld

# service iptables stop

NOTE: You may need to reference documentation for your version of Linux for proper syntax to disable the internal firewall