VERPing and Personalization (was Re: [TriLUG] Iptables help)

[Magnus Hedemark]

On Wed, 24 Mar 2004, Jeremy Portzer wrote:

> Yes, that's it.  All messages from the list to a given subscriber will
> have the same envelope sender for that subscriber.  The alternative,
> which mailman does NOT do, which is why my example is made up, is to
> include the message number (or some other identifier for the message),
> AND the e-mail address, both encoded in the envelope sender.  This means
> that a different envelope sender will appear in every message, even to
> the same subscriber.  This will cause the autowhitelist function in spam
> software to be useless, as it cannot group information by sender.

Further, anyone who is using the new greylisting functionality in the 
spamd daemon that comes with OpenBSD 3.5 will have a heck of a time with 
mailing list posts.  Each and every single post would be greylisted and 
deferred for hours unless someone took the time to manually whitelist the 
IP address.  This same greylisting methodology is probably going to be 
more widely adopted than that.  There is already a reference 
implementation written in perl as a Sendmail milter.

See http://projects.puremagic.com/greylisting/ on the philosophy behind 
greylisting, how it works, why ezmlm breaks it, and to download the 
example implementation for your Sendmail MTA (if you are running Sendmail 
anyway).

So this is why I was trying to head off Tanner in IRC and ask that he not 
enable VERP'ing with a message number if that ever comes up for 
discussion.  Every new message would signify a unique triplet and get 
stuck in the greylist for awhile, so all list posts would take hours to 
arrive, and lots of mail will get stuck on the mailing list server's 
outbound queue.