Re: lynx-dev well formed Message-ID:

[David Woolley]

> 
> Requiring a *correctly formed* Message-ID doesn't collide with any
> privacy/anonymity interests.

And can be done by using the anonymising gateway (which is generally
identifiable) or by using the software developer's domain name, although
getting guaranteed unique IDs may be a problem in this case.  (Note,
any ISP or employer who doesn't include audit trail information is
asking for complaints to their upstream supplier and being boycotted as
rogue, if any of their users ever spam.)

In practice, a client can omit Message-Id, and I have a feeling that
there is no requirement to add it later, although MTAs normally will.

> 
> > There is a candidate replacement from Windows -- is it the X-UIDL stamp?

X-UIDL is a protocol used between some POP3 servers and their clients.
It was probably mistakenly believed to be audit trail information by one
spamming engine author, whose program creates gibberish unique ID strings,
and so, on unless used locally on your inbound mail, is an even more
reliable indicator of a spam than malformed message-IDs.  Most current
spams are from throw away accounts and mailed direct or from people so
naive that they don't obscure the origin at all, so these spam engine
signatures are fairly uncommon these days.