Multics > People
04 Aug 2005

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The domain has been registered by Tom Van Vleck as an ISP-independent address for the Multicians web site. I offer this as a service to the community of Multicians, and I'm paying the costs myself.

Anyone on the Multicians list may request a mail address at, with the following properties:

Administration of this facility consists of the editor, editing a text file. If I'm unavailable, registration requests will back up. I can't be liable for mail delays caused by the ISP hosting (currently, or my own errors, or guys with backhoes, or suicidal squirrels. If these terms don't suit your needs, don't use the feature.

To request an address, fill out the registration form and check the appropriate box.

If your mail address changes, fill out the form again. If you change the mail address that forwards to without telling me, and someone sends mail to your address, there will be a bounce message sent to This message will be discarded, because I can't tell real bounces from the hundreds of spurious bounces generated by spammer activity.

Please do not use your address to sign up to high-traffic mailing lists. Too much forwarded traffic will bog down the server at and incur the wrath of Pair administrators, who may then punish us without contacting me.


Your mail address is hidden, but a stranger can send you mail via this facility. I will not sell your name or address.

To and From addresses and mail subjects are logged briefly, in order to assist in spam detection. Message content is not logged.

Use of this facility for junk email (spam) or other unsolicited commercial use is prohibited. The fee for misuse of is $5000 per message. (Not that I have ever collected a penny.)

Spam Filtering updated

Pair Networks, the ISP that hosts, implemented advanced spam filtering features: greylisting, virus rejection, black hole list rejection, and bad address rejection. You will see the following consequences on mail sent to you via the forwarder:

  1. Incoming mail from senders on the Spamhaus SBL/XBL will be rejected. I have used this list (via SpamBouncer) for over a year and have seen no false positives. This feature should cut out a large amount of spam from the major spam sources.

  2. Messages will be "greylisted" -- that is, the first time a message is sent to you from a particular sender, the sending server will be asked to try later. The delay may be a few minutes or hours, depending on the sender's mail server. Subsequent delivery attempts will not be delayed. Since many spammers never retry, this should eliminate some fire-and-forget spam. A few days' sample suggests that spam will be cut by over 50%. (Of course the spammers may alter their behavior over time.)

  3. Messages will be scanned for viruses and phishing by ClamAV and rejected if they match, again with no logging.

  4. The mail you get will have new headers, representing filtering by SpamAssassin v3 and headers will be added to the message showing the result of the checks. The header

          X-Spam-Level: ******

    indicates by the number of stars the integer value returned by Pair's SpamAssassin. You can filter on this at your mail server or client. Anything with more than 5 stars is almost certainly spam. For example, I recently saw a "419" fraud message that scored 5.5.

    I have also seen false positives from SpamAssassin on my mail, so you will probably want to implement your own whitelist.

  5. You should see less spam and not lose any mail. Initial statistics show spam cut to nearly zero.

Pair provides no logs, quarantined messages, or or backup facilities: a rejected message is gone without a trace or chance of recovery. Rejected messages will cause a well behaved sending server to inform the sender.

Please keep your own client-side spam and virus filters! Pair sometimes changes or disables its spam filters without notice, allowing spam to pass through. Also, virus filters catch previously known viruses but new unknown ones may get through ClamAV. Only you know what mail is really unwanted.

If you cannot or do not wish to implement your own spam filters, you could forward your mail to a Gmail mailbox.

If you get mail that you don't like, please do not report as a spammer. This just causes lost mail for other Multicians and wastes my time. If you register a mail address on the Multicians page, then strangers can send you mail. Deal with it, or ask me to remove your listing.

Bayes Filtering

SpamAssassin's Bayes filtering will not be used, because

SpamAssassin Headers

Here are examples of the headers you will see in mail sent to you at a address and forwarded to your real address. You may choose to filter spam based on the number of stars in the X-Spam-level header.

 Received: from (
   by with SMTP; 27 Jul 2005 09:19:31 -0000
 Received: from localhost (localhost [])
        by (Postfix) with SMTP id 01DECE9D77
        for <>; Wed, 27 Jul 2005 05:19:31 -0400 (EDT)
 X-Spam-Status: Yes, hits=6.3 required=3.0 tests=MISSING_MIMEOLE,NO_REAL_NAME
 X-Spam-Flag: YES
 X-Spam-Level: ******
 X-Spam-Filtered: a3f141a437131d5403ad894d3cc7095f
 X-Greylisting: is whitelisted

(The "whitelisted" in the X-Greylisting header means "seen this sender before.")


SPF is a proposed standard for mail and mail transfer agents that checks for forged mail. It is still the subject of debate and discussion. If it is adopted widely, we may need to change the way handles mail.

Anyone may send messages claiming that their From address is at, including spammers. Currently, does not publish an SPF record. This makes it possible for legitimate users to change ISPs without informing me. On the other hand, spam detectors cannot use SPF to check the From address versus the sending server to tell forged mail from genuine. Some spam detectors may mark messages sent from users as "possible spam" because they can't make this check.

Mail sent to your address will be forwarded by a procmail script and appear to be sent from a server at The way this mail is forwarded complies with the SPF spec as I understand it. If you do an SPF check on mail sent to you by this means, you will be checking whether mail sent by can originate at Pair. Since does not publish an SPF record, the check will indicate "no information" and your mail server will do whatever it does with such mail.

20 July 2002, updated 26 May 2005, 04 August 2005, 01 May 2006, 13 Nov 2006