UDP port 34420 of repeater has to be exposed (forwarded)
Default master port is 10405
Several Kirisun repeaters behind a single IP
Allowed count can be configured at BrandMeister configuration. In this case each repeater's port 34420 has to be exposed (forwarted) as 34420 + N, where N is sequential number from 0 up to allowed count - 1 (34420, 34421, etc).