[Mimedefang] OT: DNS sanity check

Les Mikesell les at futuresource.com
Wed Jul 4 18:38:09 EDT 2007


John Rudd wrote:
> Les Mikesell wrote:
> 
>> And you seem to have avoided reading the other part of what I quoted
>> saying how hosts that are not in DNS _at all_ are permitted with special
>> dispensation in the syntax.  I don't see how anyone who has read that
>> can claim that is a requirement for forward or reverse DNS support at
>> the sending host.
>>
> 
> Show me where RFC 2821 says that the receiver _MUST_ grant the
> alternative, as opposed to it being a means of how to handle the
> situation if the receiver decides to allow the alternative.
> 
> 4.1.3 does not say "you must accept messages from hosts without DNS
> entries".  It describes what an address literal should look like
> _in_case_ you decide to accept messages from hosts without DNS.

Please show me where it says you _MUST_ accept from IP's that do have
reverse DNS configured to match the A record before I go looking for an
equivalent mandate for the case where they don't.   I don't believe
either exists, and any decisions based on sender DNS lookups are
entirely arbitrary, not standards-based.

-- 
  Les Mikesell
   lesmikesell at gmail.com



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