[dns-operations] about the underline in hostname

Mike Hoskins (michoski) michoski at cisco.com
Fri May 30 13:43:25 UTC 2014

-----Original Message-----
From: Mark Andrews <marka at isc.org>
Date: Friday, May 30, 2014 at 6:45 AM
To: Randy Bush <randy at psg.com>
Cc: dns-operations <dns-operations at lists.dns-oarc.net>
Subject: Re: [dns-operations] about the underline in hostname

>In message <m238frwvcu.wl%randy at psg.com>, Randy Bush writes:
>> > we can't righteously complain about middleboxes that think they know
>> > what UDP/53 payloads have to look like and thus prevent EDNS from
>> > widely deployed, while at the same time saying that BIND's zone file
>> > parser knows what a host name ought to look like (even if you're right
>> > 99.9999% of the time).
>> bingo!  we seem to revel in petty rules.  full employment for nit
>> pickers?
>When you have users going "named accepted it so it must be right"
>you get all the checks being made because that is what our users
>are asking for and expecting.

Exactly, which anyone who's been on the Internet for long will remember...

I understand Paul's complaint, maybe this isn't relevant in the brave new
world, or maybe it is.  It's obviously not for one person to decide, and
as the many dated RFCs alluded to clearly show it's constructive to
periodically review stuff like this (even better if it results in
standards being updated vs everyone running off and doing things which
clearly violate published standards).

The reference to 1995 earlier in the thread painfully reminded me of times
when mail gateways with "_" in the hostname really would queue mail
endlessly because of upstream bounces.  BIND complaining about "_" before
such behavior was very useful, as it was calling out something with
real-world impact ahead of time.

Great if all the MTAs in the world have been fixed...have they really?
Are you sure?  Where else is this logic buried?  Until you can answer that
with the same 99.9999% certainty, it's useful to have anti-foot-shooting
sanity checks.  Besides, BIND users can disable it if they really want to
apply shotguns liberally to parts of their body.

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