IDN, dig and underscore

Andre Masella andre at
Sat Jan 13 17:55:18 UTC 2007

I've upgraded to bind 9.4.0rc1 form 9.4.0b4 and I've discovered they both have 
some odd behaviour when I enable IDN.

If I do:
$ dig
dig: convert UTF-8 textname to IDN encoding: prohibited character found

Removing the underscores makes it not complain. I assumed the problem was with 
idnkit, but when I tested this:
$ echo | idnconv

idnkit seems happy to pass the underscores through. It also handles:
$ echo _ldap._tcp.dé | idnconv

So, idnkit is willing to deal with names with _, but dig is not. If I disable 
IDN (either by using the IDN_DISABLE environment variable or recompiling), I 
can do:
$ dig
with no problem.

Are IDN and _ names mutually exclusive? Thanks.
--Andre Masella (andre at

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