Tastlessly following up myself:
| [...]
|
| Looking at it your way, I could guess that the difference between the
| time a message arrives at your ISP and the time fetchmail downloads it
| would, on average, be greater than the difference between the time it
| was sent and it arrives at your ISP. In other words fetcmail's polling
| time interval is likely to be greater than the time from sender to ISP.
| On the other hand, for messages where the converse is true, the
| discrepancy in the dates can be decades. [...]
That's worded incorrectly. The converse -- messages that take more
time from sender to ISP than from ISP to download are only a subset of
the exceptions. All of this is predicated, as is LuKreme's proposition,
on the notion that the Date: header accurately reflects when the message
was set. That may be so in most cases. The point is that when it's
not, the discrepancy is likely to be significant. Using Date: (or
From:, etc.) are always dubious because they're controlled by someone
other than you. And it's not only significant for forgeries and other
deliberate attempts to deceive.
The more I think about this, the more I dislike the Date: header. I
have 8 computers with 8 different times because I've never gotten
around to setting up ntp. Not only are you subject to other people
having their clocks set drastically wrong, but you're subject to
variations in clock settings on virtually every sender's machine that
makes every different Date: header like comparing apples and oranges.
The only constant, especially if the need is for sorting, is the
date/time it arrives on your machine. That's the only thing that's
totally within your control, and the only thing that is at all reliably
comparable from one message to the next -- especially if differences of
"4-6 minutes" are significant.
--
Email address in From: header is valid * but only for a couple of days *
This is my reluctant response to spammers' unrelenting address harvesting
_______________________________________________
procmail mailing list
procmail(_at_)lists(_dot_)RWTH-Aachen(_dot_)DE
http://MailMan.RWTH-Aachen.DE/mailman/listinfo/procmail