the FAQ suggest that I can input domain names with dots. On my Linux-box I have usually some common servers in the /etc/hosts like
123.456.789.0 foo.bar.boing.de foo
to reach them even when my provider DNS is broken. When I read the FAQ and the entry to the build 54 here right, then I should be able to input this as follows:
1. Leaving MAC address zero
2. entering the ip
3. putting "foo.bar.boing.de_foo" into the Hostname field
As already mentioned in the summary, when I put only "foo.bar.boing.de" into the Hostname field I get the error message "Invalid hostename. Only Characters A-Z 0-9 _ and - in the middle are allowed".
*I'm new here, so sorry for any inconvenience or stupid questions.