Command open_firewall does not work

Symptom:

The CLI command open_firewall does not work on some nodes.

Cause:

SUM is unable to open the firewall in all instances. These include: third-party firewall applications, Linux iptables DROP entries, and firewalls with complex rules.

Action:
  1. When the open_firewall command does not work, manually open the firewall and then SUM can manage the node.