Browse Prior Art Database

Anti-Spam Recommendations for SMTP MTAs (RFC2505)

IP.com Disclosure Number: IPCOM000003088D
Original Publication Date: 1999-Feb-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 20 page(s) / 50K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Lindberg: AUTHOR

Abstract

This memo gives a number of implementation recommendations for SMTP, [1], MTAs (Mail Transfer Agents, e.g. sendmail, [8]) to make them more capable of reducing the impact of spam(*).

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 5% of the total text.

Network Working Group G. Lindberg

Request for Comments: 2505 Chalmers University of Technology

BCP: 30 February 1999

Category: Best Current Practice

Anti-Spam Recommendations for SMTP MTAs

Status of this Memo

This document specifies an Internet Best Current Practices for the

Internet Community, and requests discussion and suggestions for

improvements. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1999). All Rights Reserved.

Abstract

This memo gives a number of implementation recommendations for SMTP,

[1], MTAs (Mail Transfer Agents, e.g. sendmail, [8]) to make them

more capable of reducing the impact of spam(*).

The intent is that these recommendations will help clean up the spam

situation, if applied on enough SMTP MTAs on the Internet, and that

they should be used as guidelines for the various MTA vendors. We are

fully aware that this is not the final solution, but if these

recommendations were included, and used, on all Internet SMTP MTAs,

things would improve considerably and give time to design a more long

term solution. The Future Work section suggests some ideas that may

be part of such a long term solution. It might, though, very well be

the case that the ultimate solution is social, political, or legal,

rather than technical in nature.

The implementor should be aware of the increased risk of denial of

service attacks that several of the proposed methods might lead to.

For example, increased number of queries to DNS servers and increased

size of logfiles might both lead to overloaded systems and system

crashes during an attack.

A brief summary of this memo is:

o Stop unauthorized mail relaying.

o Spammers then have to operate in the open; deal with them.

o Design a mail system that can handle spam.

1. Introduction

This memo is a Best Current Practice (BCP) RFC. As such it should be

used as a guideline for SMTP MTA implementors to make their products

more capable of preventing/handling spam. Despite this being its

primary goal, an intended side effect is to suggest to the

sysadmin/Postmaster community which "anti spam knobs" an SMTP MTA is

expected to have.

However, this memo is not generally intended as a description on how

to operate an SMTP MTA - which "knobs" to turn and how to configure

the options. If suggestions are provided, they will be clearly marked

and they should be read as such.

1.1. Background

Mass unsolicited electronic mail, often k...