The default ports are:

HBBR: 21117(TCP), 21119(TCP)

HBBS: (21114) API, 21115(TCP), 21116(UDP/TCP), 21118(TCP)

Thereby RustDesk requires more than one port and a specific port gets specified via -p, RustDesk takes the ports around this port:

Example:

• HBBR: 55002, 55004
• HBBS: (54999) API, 55000, 55001, 55003

Change ports with in system service:

• ExecStart=/opt/rustdesk/hbbr -p55002
• ExecStart=/opt/rustdesk/hbbs -p55001

(The path to the executeables may be different, adjust to them to the given installation.)