This question because both
nslookupfail when FF succeeds. Is there some other command line tool that can handle IDN (I tried with double quote the DN).
IDN domains are translated before they're queried. The browser does this conversion.
You can install the tool
idn to translate -
sudo apt-get install idn.
Enter the domain you want to translate, and press enter:
$ idn libidn 1.29 Copyright 2002-2014 Simon Josefsson. GNU Libidn is free software with ABSOLUTELY NO WARRANTY. For more information about these matters, see <http://www.gnu.org/licenses/>. Type each input string on a line by itself, terminated by a newline character. løk.no xn--lk-lka.no
You can also specify it as a parameter:
$ idn løk.no xn--lk-lka.no
You can also use a website tool, like https://www.punycoder.com/
The translated name can then be resolved using standard command line tools like dig or nslookup, or used in non-IDN-aware applications.
You can also pipe this straight into nslookup:
$ idn løk.no | nslookup Server: 10.1.12.15 Address: 10.1.12.15#53 Non-authoritative answer: Name: xn--lk-lka.no Address: 188.8.131.52