Know which ports to open on the DSA firewall for Pritunl server.
Based on this Pritunl article, it is not recommended to enable any host-based firewall on the Pritunl server:
Always use an external firewall
Avoid using software firewalls that may exist on the Pritunl server itself, such as iptables or ufw. Instead, always use a firewall that is external to the server such as a hardware firewall or AWS security groups. Only the VPN ports should be open to the public Internet.
Disable DSA firewall for Pritunl server.