[dns-operations] TLD(s) for private use

[Paul Vixie]

James Stevens wrote:
> ...  interesting to see that
> underscore in public names is astonishingly common - like SRV records,
> so I assumed underscore was reasonably well supported.
>
> https://en.wikipedia.org/wiki/SRV_record
> https://tools.ietf.org/html/rfc2782
>
> And PSL requires you add "_psl" to zones
>
> https://publicsuffix.org/

to the extent that any software will warn or kvetch about underscores, 
it will be in the context of host names -- which are owners of A/AAAA 
RRsets, or owners or targets of MX RRsets. SRV is deliberately outside 
the fold. note also, that such warnings do not have the backing of any 
IETF standard, it's just a thing that some software does.

-- 
P Vixie