Python 2.7 [Errno 113] No route to host

Check the firewall (on the server).

I stopped the firewall like Messa suggested and now it works.

service firewalld stop

I still don't understand what the problem was. I even tried using different distributions. Do all distributions have strict firewalls or something. For example Ubuntu to Ubuntu, Ubuntu to CentOS, CentOS to Ubuntu I still had the same problem (error).

You should bind the server socket to '0.0.0.0', not '192.168.178.30'.