This section describes how to modify custom firewall rules.

To modify local firewall rules, edit the following file: /etc/iptables/rules.v4

Important: Add only targeted rules for addresses and ports. Do NOT add blanket drop or accept rules. SD-WAN Gateway will append its own rules to the table and, because the rules are evaluated in order, that may prevent Gateway software from functioning properly.
*filter
:INPUT ACCEPT [0:0]
-A INPUT -p udp -m udp --source 127.0.0.1 --dport 161 -m comment --comment "allow SNMP port" -j ACCEPT 
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
COMMIT

Restart iptables service:

service iptables-persistent restart
service vc_process_monitor restart