[Asrg] Round 2 of the DNSBL BCP

[Chris Lewis]

Matthew Sullivan wrote:
> Andrew D Kirch wrote:
>> Matt Sergeant wrote:
>>   
>>>>    Some mail systems are unable to differentiate between these various
>>>>    results or flags, however, so a public DNSBL MUST NOT include
>>>>    opposing or widely different meanings -- such as 127.0.0.23 for
>>>>    "sends good mail" and 127.0.0.99 for "sends bad mail" -- within the
>>>>    same DNS zone.
>>>>     
>>>>       
>>> Not sure why this is a MUST NOT. If people are dumb enough to use a  
>>> mixed list in a broken way they get what they deserve. What's the  
>>> justification?

>> This isn't just broken lists it's broken software.  Not all software 
>> which uses DNSBL's differentiates by returned response.

> Valid point and a separate section on client configuration/usage or even 
> a separate RFC would be a good idea.

I'm contemplating doing a more general BCP on filtering (receiver end), 
or perhaps restricted to DNSBLs if the former gets too controversial 
(like if I start ragging about SAV or C/R ;-)  Main things would be 
"reject, not block", "useful, not necessarily fully revealing" error 
codes, plus various attitudinal adjustments ;-)  I have this 10 point 
thing laying around somewhere that forms the basis for the ideas.