Network Working Group
Internet-Draft C. Kularski
Expires: March 2004 Highland School
of Technology
Category: Informational September 2003
Compound Procedures for SPAM Control
draft-kularski-spam-spamreduce-04.txt
Status of this Memo
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all provisions of Section 10 of RFC2026.
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Abstract
This document describes procedures that can be put into place to
significantly reduce the amount of SPAM received by a user. The
procedures are implemented on the SMTP server.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [i].
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1. Introduction
The procedures outlined in this document require a complex SMTP
implementation that is capable of handling the addressing schemes
required by this document. The SMTP service itself should remain
in compliance with all standards and specifications.
2. Address Structuring Considerations
The procedures in this document are easiest to implement using a
sub-domain for each user, such as "user.example.net". The sub-
domain SHOULD NOT be defined explicitly, it should be assigned as
a wildcard (*) Mail Exchanger RR.
To avoid DNS issues completely you can use a dotted (.) or
hyphenated naming structure before the "at" (@) symbol. The more
creative you are with the design of your address schema the fewer
SPAM messages you are likely to receive.
3. Email Addresses
There are three main classifications of email address which must
be defined.
Addresses for Automated and Non-Trusted Sources û This set of
addresses is defined by the user. There MUST be a way for the user
to easily change his/her list of available addresses quickly and
easily. The user will need the ability to add and delete addresses
from the list. The user will assign a unique address to each non-
trusted email source. If the source misuses the address, then the
address can be disposed of by deleting it from the list. Mail
received by these addresses should be deposited in the user's
primary mailbox. If a user needs an excessive amount of non-
trusted source address a wildcard address can be used for this
purpose (with the ability to kill abused addresses), but it is not
recommended.
Address for Personal Communication û The address for personal
communication is a single email address defined by either the user
or the administrator. This address will most likely be the one
used as the primary mailbox for the user. The user should give
this address only to human sources that are unlikely to spread the
address.
Addresses for Common Services, Roles and Functions û Addresses
defined by RFC 2142[ii] should be directed to the mailbox of the
appropriate function on the primary domain (example:
abuse@user.example.net is delivered to abuse@example.net).
4. Considerations for Each Address Type
Each address type has its own special needs for them to be used to
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their full potential and to allow the least amount of SPAM in.
Addresses for Automated and Non-Trusted Sources û These addresses
MUST be unique to each source. Mail for these addresses can be
filtered to add an additional level of SPAM elimination, but the
nature of these addresses will significantly reduce the amount of
SPAM received.
Address for Personal Communication û This address should be
protected in several ways. First, the address should not be widely
distributed and should NEVER be used for newsgroups, web pages or
any purpose where it will be publicly viewable. Additionally the
mailbox can use a whitelist (and blacklist) system to authorize
senders or you can use a score-based SPAM detection system.
Addresses for Common Roles, Services and Functions û due to the
nature of these addresses they should not be extremely
restrictive, but due to the nature of SPAM attacks some protection
is advisable.
5. Possible Special Addresses
In addition to the addresses for non-trusted sources temporary
addresses that expire after a certain amount of time has elapsed
can be used for situations where SPAM is imminent, such as
newsgroup communication.
6. Address Examples
Sub-domain Non-trusted source û spammer@user.example.net
Dotted-user Non-trusted source û spammer.user@example.net
Hyphened-user Non-trusted source û spammer-user@example.net
Sub-domain Personal û user@user.example.net
Dotted (or Hyphened) Personal û user@example.net
Security Considerations
The information in this document introduces no Security Concerns.
References
i Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997
ii Crocker, D., "Mailbox Names for Common Roles, Services and
Functions", RFC 2142, May 1997
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Author's Addresses
Curtis M. Kularski
219 Best St
Bessemer City, NC 28016-9330
United States
Phone: +1 (704) 629-2498
Email: curtis@kularski.net
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Acknowledgement
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