[Mailman-Users] Is Mailman 2.1 not plushack aware?

Jay Ashworth jra at baylink.com
Sun Jun 2 03:06:18 CEST 2013

----- Original Message -----
> From: "Bill Cole" <mailmanu-20100705 at billmail.scconsult.com>

> It is altogether always wrong for ANY mail software outside of a domain
> to parse the local part of an address in that domain except for a tiny
> handful of standard special local parts (e.g. "postmaster"). The use of
> '+' as a tag delimiter is widespread but it is not in any sense a
> "standard" and comes nowhere near universality. There is no way for a
> Mailman instance to know which domains make "user+tag" and "user"
> equivalent and which do not, so canonicalizing as you suggest would
> result in breakage.

Noted.  FWIW, in 30 years, I have not seen *any* use of the + sign in 
LHSs which did not appear on its face to be a plushack... though as you
imply, I can't really tell for sure.

> Beyond that risk of breakage, "canonicalizing" local parts which one
> does not own is wrong in principle: it violates the core assumption
> which makes Sendmail-style plus-tagging useful. The tagged address is
> supposed to be unique in the view of everyone except its owner and the
> owner's delivery agent, which can easily discern that an address is
> tagged (maybe with '+' but maybe not) and then handle the address and
> tag in whatever locally customized manner their whims dictate. Outside
> entities should never try to guess what those whims are at any
> particular time and more importantly should never translate an address
> from what it actually is to what their guesses about the owner's whims
> implies.

Ok, I guess I'll buy that.  I appreciate you showing the work for me, Bill;
I hadn't thought it all the way through.

> Note: you might look at my address for this list and make any of a
> number of reasonable guesses about how its structure (which *IS*
> significant) relates to its delivery and handling. Most would be
> operationally wrong and none would be complete. I tag addresses in
> opaque ways precisely because of past rude & clueless attempts by
> others (mostly spammers) to break + tagging.


-- jra
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA               #natog                      +1 727 647 1274

More information about the Mailman-Users mailing list