From: ichudov@algebra.com
Date: Wed, 12 Feb 1997 21:12:00 -0800 (PST)
To: Jim Choate <ravage@EINSTEIN.ssz.com>
Subject: Re: subscribe
Message-ID: <199702130512.VAA29302@toad.com>
MIME-Version: 1.0
Content-Type: text/plain


Jim Choate wrote:
> 
> 
> Hi Igor,
> 
> > I will not impact me negatively. I do, however, suggest very strongly
> > that hosts should be subscribed to each other thgrough another mechanism
> > and not majordomo, in order to prevent mail loops, header rewriting and such.
> 
> Suggestions? What I had in mind was that any messages that get sent on
> cpunks@ssz.com get sent over to algebra. One mechanism I would like to play
> with is a 'linked list' of remailers. Remailer A sends only to B and
> receives only from C...
> 
> 
>                                A
>                              ^   v
>                              C < B

> Then to stop loops B deletes all outgoing mail from B. Since email can be
> forwarded from many sites the search must traverse the entire forward chain
> killing the message if B appears as a source. I suspect a simple procmail sort
> can accomplish this. My next step is to brush up on my procmail. I hope to
> have something in a couple of days that will allow you to subscribe
> cpunks@algebra to cpunks@ssz and both ends will be filtering.

Here's how I do it (it is pretty close to your proposal): 

1) I delete duplicate messages (by looking up the database of
message-IDs) right away
2) I bounce all incoming messages to several other list servers
3) I pipe the article to majordomo for distribution.

Note that majordomo changes headers and I wuold like to feed
other servers with UNCHANGED articles.

Here's the .procmailrc that takes care of this:

(OTHER_HOSTS will be redefined to include, e.g., cypherpunks@ssz.com)

# Please check if all the paths in PATH are reachable, remove the ones that
# are not.
#
# NOTE: I use lockfiles extensively (and even excessively) because
# I do not want to overburden the system. Since I am on a
# PPP link that is not always on, sometimes large amounts of 
# submissions come in simultaneously and that may impair
# performance of the overall system. You do not REALLY need
# to use these lockfiles otherwise.
###################################################################

PATH=/bin:/usr/bin:/usr/local/bin:$HOME/bin
MAILDIR=$HOME/Mail	# You'd better make sure it exists
DEFAULT=$MAILDIR/mbox
# VERBOSE=ON
LOGFILE=$MAILDIR/from
LOCKFILE=$HOME/.lockmail

OTHER_HOSTS="cypherpunks@zzzz.com"

:0 c
$MAILDIR/allmail

############################################################ mailbombing
############################################################ end mailbombing

:0
* ^TOcypherpunks
* !^X-Loop:
* !FROM_MAILER
* !FROM_DAEMON
{
  #
  # This recipe removes duplicates!
  #
  :0 Wh: msgid.lock
  | formail -D 128000 msgid.cache

  # send it to all other hosts
  :0 c
  !$OTHER_HOSTS

  # add X-Loop:
  :0 fhw
  | formail -I "X-Loop: cypherpunks@algebra.com"

  # send it to people
  :0 c
  | cypherpunks-send-subscribers

  # Accounting, logging
  :0
  | cypherpunks-accounting
}

:0:
* ^TOcypherpunks-request
$DEFAULT

# all the rest is trash
:0
$DEFAULT

# thats where it should be
#/dev/null

> Another nice advantage of this architecture is that 'rings' of remailers can
> be interconnected by simply sending output to more than one site. Might even
> be a good stability rule, "Never have a remailer send to more than 1 machine
> in its 'own' ring". I see no limit other than resources that would limit the
> number of rings an individual remailer might be in.

A very good point.

> The address is 'cypherpunks@ssz.com' but as alluded to above. I would  like
> to let it run 1 way for a day or so to get an idea of the stability of our
> network link. You might consider creating a bogus username on your end.
> Subscribe that user to the SSZ remailer and to your own mail list. Then use
> procmail to filter all outgoing mail of that user since its incoming would
> be from your list and its outgoing would go to mine, which then forwards
> them to your list. We might want to call the bogus user 'gatekeeper'.

Yes, we really should make darn sure that no loops are poissible
before inviting people to subscribe to our lists.

> If its agreeable lets get together on the cpunks-hosts list tomorrow and
> discuss this a little more.
> 
> If you don't mind, please forward this to the cpunks@toad list with your
> responces. I would like to expose it to a little criticism.
> 



	- Igor.