🚀 go-pugleaf

I've just finished testing and uploaded binaries for GremNOS v0.3f (with
luck, just in time for ppint, who was migrated just over an hour ago).

v0.3f adds two significant improvements to the POP3 side of things
compared to the previous v0.3e:

(a) There's a new wildcard-based system that, if used, causes GremNOS to
    download the message header via POP3 and parse it to find the sender
    and recipient (effectively replacing the functionality that used to
    be available with Demon's *ENV POP3 extension) -- it's nothing like
    as efficient as *ENV, because it has to download and inspect the
    entire header rather than just read a short (five line) response,
    but it does work.  I hope it won't be unacceptably slow for those
    using a modem!

(b) If the sender isn't known (because you haven't used the *ENV or
    wildcard systems to find it) and you have a non-empty MAILKILL file,
    the message header can (optionally) be downloaded and parsed to find
    the sender, ready to check against your mailkill rules: if this is
    not done, mailkill checking doesn't happen at all.

I've also improved the handling of unusual mailbox names to make it less
likely that messages will be rejected because of invalid filename
characters like * in the recipient address.  (Those of you following d.s
will know that * and ? among others are perfectly valid characters in
the local-part of e-mail addresses, so this isn't as silly as you might
think.)

As with 0.3e, the following new builds can by downloaded from my
ashes.org.uk web site (there's no index page, just files) -- the full
set of builds is available this time:

http://www.ashes.org.uk/gremnos/lrge_03f.zip    Large build
http://www.ashes.org.uk/gremnos/lite_03f.zip    Lite build
http://www.ashes.org.uk/gremnos/pplt_03f.zip    ppint's custom Lite build
http://www.ashes.org.uk/gremnos/pklt_03f.zip    PK-Lite (packet driver)
http://www.ashes.org.uk/gremnos/twlt_03f.zip    TW-Lite (TextWin Lite)
http://www.ashes.org.uk/gremnos/tplt_03f.zip    TP-Lite (TextWin PK-Lite)


Wildcard header scanning
------------------------

The wildcard system in (a) above is used if the fourth argument to the
"pop3 collect" command is "*wild" (cf. the old "*env" argument), e.g.

  pop3 collect mail.demon.co.uk administrator@host.demon.co.uk pass *wild

You will also need to set the wildcard pattern with the new "pop3
wildpat" command; there is no default pattern hard-wired in, because it
would be very specific to the current state of Demon's new platform and
might stop working in the future.  For the new Demon mail platform, it
should currently be set thus (put it in your AUTOEXEC.NET):

  pop3 wildpat ">Received: from *[ 	]by *.inty.net *[ 	]for <**>*"

The stuff in the two pairs of square brackets [ ] is a space (ASCII 32)
and a tab (ASCII 9) -- check this carefully if you cut-and-paste the
line from this article, because if you don't have the tab character in
there, the pattern won't match the header fields created by the new
platform.  (The space is belt-and-braces, in case they decide to stop
using tabs and revert to the spaces that every other server uses.)

A quick explanation of the unusual bits of this wildcard pattern:

 * The ">" at the beginning tells it to use the *last* match found
   rather than the first; when using the catch-all administrator
   mailbox, all the "Received:" fields except the last contain
   administrator@yourhost which isn't a lot of help.  (Turnpike falls
   foul of this.)

 * The unusual "**" near the end tells GremNOS which part of the pattern
   contains the actual address it's trying to find.


Mailkill header scanning
------------------------

As noted in (b) above, if you have a MAILKILL file but the sender
address is unknown at the point where mailkill rules are checked,
e.g. because you haven't used *env (on the old platform) or *wild (on
the new one), it can download the header via POP3 and scan it for the
"Return-Path:" header field -- if this isn't done, the mailkill rules
are not checked at all and the sender is regarded as approved.

Whether this header downloading and scanning takes place is controlled
by the "pop3 findsender" value (0, 1 or 2):

  0  Never do it: unknown senders are approved

  1  Only do it if you have a non-empty MAILKILL file

  2  Always do it (which means that the sender address will appear in the
     log files if the message is rejected due to an unknown recipient
     address, for example).

The default is "pop3 findsender 1".

I think that's all the important stuff: I've been running an earlier
version of the wildcard scanning for a few weeks, and have had no
problems, so I'm pretty confident that it all works as it should.

I'll upload the source files and proper release notes when I get a
moment.  In the meantime, please try it out and let me know if you have
any questions, problems etc.

-- 
Simon Turner                                    DoD #0461
simon@twoplaces.co.uk
    Trust me -- I know what I'm doing!          -- Sledge Hammer