[net-dns-users] SOA rname as mailbox

Dick Franks rwfranks at acm.org
Tue May 19 00:30:05 UTC 2015

On 18 May 2015 at 17:28, Rob Foehl <rwf at loonybin.net> wrote:

> It appears that Net::DNS::RR::SOA->rname now returns a formatted address
> via Net::DNS::Mailbox1035 instead of the raw value.

Section 3.3.13 of RFC1035 says that RNAME represents a mailbox.

Section 8 defines the syntax to be RFC822 and specifies the encoding of a
mail address _inside_ the domain name system.

As the transformation is defined in RFC1035 and Net::DNS attempts to
implement RFC1035, the mailbox encoding process should occur somewhere
inside Net::DNS and not be left for the user to do.

Your program is _outside_ the domain name system, so the mailbox
representation provided by soa->rname() is defined by RFC822.

  It's not clear when this changed -- somewhere between 0.66 and 0.82, but
> I can't find any documentation or notes in the change history to that
> effect.

This change occurred in 0.69 as part of the changes needed to support
non-ASCII domain names.  The logical inconsistency of the pre-0.69
behaviour was exposed during that development.

The introduction of Net::DNS::Mailbox was noted in the change log for 0.68.
You are correct that the subsequent change in behaviour of soa->rname() was
not mentioned.  This was an oversight for which I apologise.

> What's the recommended method to get at the domain form now without
> digging around in the object?  Just feed the rname back through
> Net::DNS::Mailbox for the string value?

The only thing you can do with a RFC822 mail address is to address mail.

There is absolutely nothing useful you can do with the wire-format domain
name representation.

The question therefore does not arise in the real world, or if it does, it
is out of scope for Net::DNS.

All of this was discussed at length on this list in 2012/2013

Dick Franks
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