Subject: Re: [domainrep] reusing A records, was I-D.*-reputation-*.01

From: "John R. Levine" <[email-masked]>
Date: 29 Oct 2011 07:35:21 -0400

>For that matter, please show /any/ negative consequences other than
>offense to the sensibilities of purists.

There's the well known problem that abandoned DNSBLs are often 
reregistered by speculators who install a wildcard A record, thereby 
making the former DNSBL appear to list the world.  One can argue that this 
is a self-inflicted wound by people who outsource their mail management to 
strangers and don't check what the strangers are doing, but it's certainly 
the case that if DNSBLs had used a different RR type, this particular 
problem wouldn't occur.

Given the practical difficulty in adding new RR types to real world DNS 
software, I happen to agree that using A records was a reasonable choice. 
In the as yet hypothetical world where adding new RR types is easy, they 
should have used a different RR type, but we don't live there.

I also agree with Andrew (who I talked to at the airport this morning) 
that using A records for non-address data is fragile, since A wildcards 
are so common.  Although it's still a hack, it'd be a lot less fragile to 
use TXT records with a known tag at the begining of each record,

R's,
John