Address Munging FAQ:
Spam-Blocking Your Email Address

This FAQ is intended to be a concise discourse on "spam-blocking". Otherwise known as "munging", or breaking one's email address, this is usually done when posting to Usenet, for the purposes of avoiding junk email. An equally important purpose for this FAQ is to suggest ways to mung that minimize possible damage to third parties.

Contact the author/maintainer: [email protected]

DISCLAIMER:

This document reflects the opinions of the author. This document is provided "as is" without any express or implied warranties.  While every effort has been taken to ensure the accuracy of the information contained in this article, the author/maintainer and/or contributors assume(s) no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein.

Table of Contents

1. Table of Contents

2. Basics
2a. Who is responsible for this FAQ?
2b. What is the purpose of this FAQ?
2c. When was this FAQ last updated?
2d. Where can I get it?
2e. Credits & Contributors

3. Definitions
3a. What does 'spam-blocking' or 'address munging' mean?

4. Actions
4a. Why should I mung my address?
4b. Why should I NOT mung my address?
4c. How should I mung my address?
4d. How should I NOT mung my address?
4e. If I mung, when should I be sure to use my REAL address?
4f. What else can I do besides munging to avoid junk email?
      (AOL members can try this)

2. Basics

2a. Who is responsible for this FAQ?

WD Baseley. Use [email protected] to contact the author regarding this FAQ.

2b. What is the purpose of this FAQ?

This FAQ is intended to be a concise discourse on "spam-blocking". Otherwise known as "munging", or breaking one's email address, this is usually done when posting to Usenet, for the purposes of avoiding junk email. An equally important purpose for this FAQ is to suggest ways to mung that minimize possible damage to third parties. The author further intends that the FAQ be presented in a fashion that can be understood without need of a doctorate in computer science; those desiring more depth and/or technical information are referred to the sources listed in the the Email Abuse Resource List.

2c. When was this FAQ last updated?

December 14, 1997.

2d. Where can I get it?

This FAQ will be posted to news.admin.net-abuse.email once per month. The latest version is always available at:
URL: http://members.aol.com/emailfaq/mungfaq.html
TEXT: ftp://members.aol.com/emailfaq/mungfaq.txt
It will also be posted to other newsgroups, not all of which are known as of now.

2e. Credits & Contributors

The genesis of this FAQ was Gregory Byshenk's FAQ titled, "Help! I've Been Spammed! What do I do?" Sundry other folk who have discussed, harangued, badgered, cajoled, and otherwise assisted in bringing it to its present state, are held in grateful regard by the author.

3. Definitions

3a. What does 'spam-blocking' or 'address munging' mean?

Both terms refer to the same thing - from this point on, the author will use only the 'munging' term to refer to the practice.

Address munging is the act of modifying one's email address so that email sent to that address will not be delivered to the person doing the modifications. Typically, this is done in posts to Usenet, in order to avoid receiving unsolicited commercial/bulk email (UCE/UBE).

The Jargon File defines 'mung' as `Mash Until No Good', probably originating at MIT; sometime later the recursive acronym `Mung Until No Good' became popular. It means 'to make large changes to a file', or 'to destroy data either accidentally or maliciously'. It was probably derived from 'munge', which is why you will see both words used to describe the practice. Then of course there are the Chinese beans.

Subject: 4. Actions

4a. Why should I mung my address?

• It is an effective way to avoid junk email.

Junk emailers "harvest" email addresses from Usenet posts. Most address harvesting software used by junk emailers does not discriminate; anything with an '@' sign is considered an address. By changing what appears in the From: and/or Reply-To: headers of Usenet posts, the amount of unsolicited bulk/commercial email (UBE/UCE) received drops considerably.

• It is easy to do compared to other methods of avoiding UBE/UCE.
  
• It lowers the percentage of good addresses harvested by the address thieves.
  

4b. Why should I NOT mung my address?

• It breaks the automated 'reply by email' feature found in most newsreaders, forcing people to manually de-mung the address in order to email topical replies to your posts.
  
• If you use the same software for Usenet and email, you will have to change the address regularly, to avoid sending regular email with a munged address.
  
• It violates RFCs, the rules upon which Usenet is built.

(It should also be noted that munging does not automatically cause messages to bounce back to junk emailers; if you are considering munging for this reason, you would not accomplish your goal. Also, depending on what and where you post, a junkster *may* take the time to manually de-mung your address, just for spite.)

4c. How should I mung my address?

IMPORTANT! Make sure that modifications to your email address do not violate any of the policies of your service provider!

• Be creative with your mung, and change it often as well. These steps will prevent harvesters from picking up on patterns, and possibly changing their software to defeat them.
  
• Make it obvious to humans.
  DO: yourname(AT)example(DOT)com
  DO: [email protected] (Replace Z with E)
  DO: [email protected]
  DON'T: [email protected]

• If you decide to add a "spamblock" to your existing address, put it on the right-hand side of the @ sign. This avoids making your provider's email server handle undeliverable mail.
  DO: yourname@-REMOVE_THIS-example.com
  DON'T: [email protected]

• Tell folks how to de-mung your address somewhere in your message. The signature (sig) that gets added to the end of each message is a good place to do this.
  DO: "To reply via email, remove '-REMOVE-THIS-' from my address."
  DO: "Real address is myrealname AT example DOT com"
  DO: "Replace all the Z's with E's to reply"
  

NOTE:  DO NOT put a directly usable address in your sig, because many harvesters collect everything with an @ sign in it.
DO: "Send email to myrealname; ISP is example DOT com"
DON'T: "Real address is [email protected]"

4d. How should I NOT mung my address?

IMPORTANT! Do not make up domain names! Most of them actually exist, and your fakery could cause them a lot of woe. Certain domains are already virtually useless because of folks using them in mungs and forgeries.
DON'T: [email protected]
DON'T: [email protected] (instead of COM)

• Do not use a totally faked address, especially one that looks real.
  DON'T: [email protected]

• Do not make it *too* obvious by using a 'standard' mung. Invent your own, or choose an unusual one of those you have seen. If everyone uses the same mung, it becomes easier for junk emailers to strip them out.
  DON'T: [email protected]
  DO: [email protected]

4e. If I mung, when should I be sure to use my REAL address?

• When sending email.
  
• When subscribing to a mailing list.

4f. What else can I do besides munging to avoid junk email?

• Ask your provider to give you the option of having the most egregious junk emailers blocked by them.
  
• If your ISP/domain offers one, you can use a "spam sink" address; all email to this address should be deleted, unread, by your ISP.
  EX: [email protected]

NOTE: Usenet conventions allow topical replies to posts, so if you choose this you should include a usable address somewhere in the message.

• Use filters to sort email either at the server or after it has been downloaded to your machine. Most standalone email software includes filters, and some of them (notably Pegasus Mail) are free.  Those who have shell accounts, or server access, can use a Unix tool called procmail to handle messages as they arrive at the server. Filtering rules can be VERY simple and still be effective.

AOL members: as of this writing, AOL software does not allow munging of addresses in Usenet posts. A possible solution:

• Create a new screen name just for posting to Usenet
• Use Mail Controls to set that name to receive NO email at all
• Use the sig to tell people what your replyable address is
  
  EX: "DO NOT REPLY TO [email protected]. It is used for posting to Usenet only, and does not accept any email. To reply by email, use myrealname AT aol DOT com."

End of the Address Munging FAQ