On 2009-11-28 at 16:45 +1300, Craig Whitmore wrote:
> On Sat, 2009-11-28 at 12:01 +0900, Randy Bush wrote:
> > > hostnames (and FQDN's) aren't allowed to have _'s in them so exim is
> > > rejecting it correctly.
> >
> > fqdns can have anything in them. just wait for idn deployment.
>
> hostnames cannot have _'s in them.. _'s can be used but not for
> hostnames of computers on the internet. (feel free to use them if you
> are not connected to the internet)
>
> I don't want to argue.. read the RFC's.. read
> http://en.wikipedia.org/wiki/Hostname
>
>
> if you want to put a _ in your hostname or accept _'s in HELO's then its
> up to you.. but aren't playing nice on the internet
Just as a minor heads-up, you're talking to the author/co-author of,
amongst others (I'm limiting this to DNS-related ones):
RFC 2181 Clarifications to the DNS Specification.
RFC 2182 Selection and Operation of Secondary DNS Servers. [BCP 16]
RFC 2870 Root Name Server Operational Requirements. [BCP 40]
RFC 2901 Guide to Administrative Procedures of the
Internet Infrastructure.
RFC 3152 Delegation of IP6.ARPA. [BCP 49]
RFC 3363 Representing Internet Protocol version 6 (IPv6) Addresses
in the Domain Name System (DNS).
RFC 3681 Delegation of E.F.F.3.IP6.ARPA.
So you're asking the author of many of the operational RFCs relating to
DNS to ... uhm ... nevermind.
Standards-track RFCs reflect the consensus standard of the IETF
participants at a given time; things change. Internationalisation of
domain-names is forcing a change of many previous assumptions; this is
part of why Exim has the dns_check_names_pattern option and documents
how to use this with allow_utf8_domains.
Most resolver libraries long ago stopped caring. It would be an
interesting world, where one can use 观音 as a hostname, but can't
include an underscore. So I think that prohibitions on underscores will
disappear within five years, in practice if not de jure.
For now, I'd be inclined to allow underscore on the submission port but
not the MX port. This isn't currently possible in Exim.
Regards,
-Phil
