try adding a subnet mask
host all username 0.0.0.0 0.0.0.0 md5
or a cidr mask
host all username 0.0.0.0/0 md5
that's it. I don't know, why I only wrote 0.0.0.0...
Thats cleary my fault.
Thanks for all your help.
Greetings,
Urkman
try adding a subnet mask
host all username 0.0.0.0 0.0.0.0 md5
or a cidr mask
host all username 0.0.0.0/0 md5