Thank you very much for help, now i am with 2 keyboards connected to each machine(client and server), and i think i mistakenly entered something at the first line that i was intended to write on the client machine.
Server has started and one more problem is that i cannot connect to the server, even if they are in the same network.
Ping command is working fine but other things (i tried 7dtd server and minecraft server) are not working.
Also the server machine have access to the internet, so cable and network hub is functional.
If possible, could you tell me what to investigate to solve the problem?