underscore in A or PTR records

[Reindl Harald]

Am 17.02.21 um 09:50 schrieb ONRUBIA AVILES Carlos (CCS/MST):
> Hello,
> 
> Thanks for these clarifications.
> The issue we face is that a telecom provider ask us to implement a PTR record with a name like "example_try.net"

point out to that provider it's a bad idea and that they should know that!

i can't count how often developers wasted hours because they used a _ in 
the hostname and MSIE had strange cookie behavior with the illegal 
hostname at the final tests after development web applications on Firefox