UCS-Debian Client sees no Server ... Server sees no Client

Hello there.

I have a Windows PC with UrBackup server
I released the ports in the firewall.
I can reach the ports 55413-55415 from outside with Telnet
On the UCS Debian I have tested both ways to install the client.

Both the finished binary and the way via the compiler.
Both worked (each on a virgin system) and both don’t show any errors.

I disabled the firewall of UCS-Debian. (for testing)

Server and client are on a switch in a local network

But the server cannot display clients and the client says he cannot see a server.

Windows clients on the same network are displayed and work immediately after installation

Translated with www.DeepL.com/Translator (free version)

root@ucs-7083:~# netstat -npl | grep urbackup
tcp 0 0* LISTEN 2739/urbackupclient
tcp 0 0* LISTEN 2739/urbackupclient
tcp6 0 0 :::35621 :::* LISTEN 2739/urbackupclient
tcp6 0 0 :::35623 :::* LISTEN 2739/urbackupclient
udp 0 0* 2739/urbackupclient
udp6 0 0 :::35622 :::* 2739/urbackupclient

As your netstat session shows, local client discovery uses ports 35621-35623, as documented in the UrBackup Admin Guide. Ports 55413-55415 are for the Web and Internet interfaces.

The core client process listens on port 35622 UDP for UDP broadcast messages from the server and on receiving one sends a message with its name back to the server. As name the Windows computer name is used. It listens on port 35623 TCP for commands from the client interface process and the server and on port 35621 TCP for file requests from the server.