Re: 3028bis, section 4.2, paragraph 2

[Philip Guenther <[e-mail]>]

On Thu, 8 Feb 2007, Tim Showalter wrote:
> Mark E. Mallett wrote:
>> So it sounds like you are saying that the new text about how the count
>> of Received headers MUST be larger is connected to that.  That since
>> some implementations may choose to count Received lines to avoid loops,
>> all implementations must have a higher Received line count when doing
>> redirect.

Yes.  That seemed to be the list concensus, based on the thread with 
subject "Comments on draft-ietf-sieve-3028bis-09 from Eric Rescorla" at 
the beginning of November.  I didn't see any one arguing against mandating 
the addition of Received header fields by 'redirect' back then, so I took 
it to be agreed.


> If two (or more) implementations are configured to loop, just one adds 
> Received headers and uses them for loop control, that's enough to stop the 
> loop.

Yes, but if just one implementation (in the "code base" sense) does _not_ 
add Received header fields and it is installed at multiple site, then it 
can sustain a loop.  Heck, an implementation with no loop control can be a 
mailbomb generator if it supports multiple redirects for a single message: 
it would just a sieve script that redirects to its own address as well as 
the victim address.


> I can't imagine why anyone wouldn't add Received anyway, just based on 
> advice in 2821 (and common sense).

Common sense is as common as a sense of humor, apparently.  (References to 
solving the Halting Problem were removed from 3028bis after multiple 
reviewers expressed their dislike for the text.)


Philip Guenther