Firewall ports to leave open #

By default, all the ports that Synergy uses that are not public are firewalled by the Docker Swarm configuration, but if you still want to use another firewall layer, here is a list of ports that must be open for full functionality:

• 53 (UDP+TCP)
• 67-69 (UDP+TCP)
• 80 (TCP)
• 88 (TCP)
• 139 (TCP)
• 443 (TCP)
• 445 (TCP)
• 873 (TCP)
• 3000 (TCP)
• 4000-4002 (TCP)

When running the SSL setup or renewal function, the app needs to access Let’s Encrypt’s API endpoints AND the app needs to be able to access itself on its own URLs - note that you’ll want to set http on these URLs if SSL is not set up.

If you’ve implemented any iptables rules on the SynergyCP master, check that these aren’t blocking outbound traffic, or traffic from the Docker containers that make up the app back to the app URLs.