SRS comments/questions

In Shevek's "The Sender Rewriting Scheme" (6/5/2004 version), Section 
4.3 (The Timestamp) it says the timestamp has 1-day resolution mod 2^10, 
which gives a 3.5 year cycle before repeats.  Actually, 2^10/365 is only 
2.8 years.  Or am I missing something?

Also, I'm curious how this works with greylisting.  Does SRS update the 
timestamp for each delivery attempt, or only for each message?  If it 
updates for each delivery attempt, that would cause the same message to 
be greylisted twice if it happened to be sent shortly before the 
midnight hour (which might be business hours, if unix_time is in GMT and 
your business is elsewhere).  Even if it only updates the timestamp 
once, this will still cause daily greylisting slowdowns, but I guess 
that can't be avoided.

A bit OT, but SPF seems doomed to failure.  It can't work unless 
everyone decides to do SRS, which probably won't happen.  So, as a 
sender, the best strategy is to create an SPF record that lets anyone 
spoof your domain (so mails that get forwarded by non-SRS-compliant 
sites dont' get rejected).  I'm curious what the advantages to SRS are, 
considering that SPF can't possibly work.  (I recognize it's needed 
since you might forward to a site that does SPF.  But until *everyone* 
does SRS, SPF can't take off.  And until SPF takes off, there's not much 
need for SRS....)

Damian Menscher
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