Re: "Header Reordering", yet again

On Tue, 31 May 2005 14:05:13 BST, Paul Smith said:

> If you specified that the timestamp on the Received-SPF field MUST be 
> IDENTICAL to the timestamp on the Received: line added by the same server, 
> that might solve some problems.
Nope.  I've seen a piece of mail pick up 5 different Received: headers with
the same HH:MM:SS timestamp legitimately (OK, so it *was* a high-performance
mail system sized for max daytime loads, and 2AM on a holiday during a vacation 
;)

And that was with 3 servers that were NTP-synched.  What happens if ServerA
sends mail to ServerB, and ServerB's clock is slightly behind? (I've seen
stuff go 8-10 hops, and the next hop still got a timestamp a few seconds earlier
than the first hop - if the clocks were closer together, they'd collide).

If you're planning to go down this bad-idea path, you *really* need to specify
that the two headers are linked with some glob that has msgid-like uniqueness
properties....

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