IBM AH0QXML User Guide - Page 17

Chapter 1. Introduction

5

±

Mail trying to entice you to visit certain sites, often pornographic, or of very

questionable nature.

–

Mail of this nature is often directly to the point.

“

Wanna see more of me?

Click here.

”

or

“

I can't believe it, you have to see this! Click here.

”

This type

of spam is often paid for by the site in question. Advertising rates for big

commercial sites are very high, for the simple reason that a great many

people will see them.

–

If an unscrupulous site can demonstrate through an independent source

that they have a very large hit rate, they will entice advertisers hoping to

sell products or services via their site. The more people who innocently

click on the link, the higher the hit counter will soar. Many spammers also

take advantage of the fact that HTML mail can contain moving images. For

instance,

“

Click on the Monkey to win $10,000

”

and when you click on the

monkey then you are sent to the site the spammer intended.

±

Malicious mail designed to interrupt regular Internet traffic or flood mailboxes

or mail routers.

–

This last category is the type of spam the average person will be least

likely to come across. It consists of malformed messages designed to

disrupt mail services, often by attempting to crash SMTP routers. There

are an infinite number of possible combinations of mail messages that a

spammer can create. They can deliberately send empty attachments, bad

headers, looping addresses, incorrect control characters within critical

routing fields, or any of a myriad of other things to attempt to cause mail

blockages.

–

Mail routing applications such as Lotus Domino have very robust SMTP

defenses in place to avoid and prevent these types of attacks. Defensive

code included in the product will reject malformed messages which could

have provoked error conditions. Normally, mail needs to conform to a strict

standard in order to be accepted. If not, the SMTP router will simply reject

it. However, hackers, crackers, and malicious spammers are constantly

changing the methods they use to attempt to disrupt services. Inevitably,

an unprotected system will eventually fall prey to this type of message.

For more information about what constitutes spam, see the publicly available

RFCs located here:

±

RFC2505 (

http://www.ietf.org/rfc/rfc2505.txt?number=2505

)

±

RFC2635 (

http://www.ietf.org/rfc/rfc2635.txt?number=2635

)

Section	Page
Front cover	1
Contents	5
Notices	7
Trademarks	8
Preface	9
The team that wrote this redbook	9
Become a published author	11
Comments welcome	12
Chapter 1. Introduction	13
1.1 Definition of spam	14
1.2 Categorizing spam	14
Chapter 2. Preventing unwanted e-mail and spam	19
2.1 Spam avoidance techniques	20
2.1.1 Passive harvesting attacks	20
2.1.2 Avoiding harvesting	21
2.1.3 Confusing the harvesters	22
2.1.4 Inform Users	22
2.2 How to block spam	24
2.2.1 At the gateway	25
2.2.2 At the server	25
2.2.3 By the end user	26
2.2.4 Selecting the best approach	26
2.2.5 Managing the ongoing anti-spam campaign	27
2.2.6 Summary	28
Chapter 3. Domino 6 anti-spam architecture	29
3.1 The Domino messaging environment	30
3.2 Domino 6 messaging components	32
3.2.1 SMTP Listener/Server	33
3.2.2 Router	35
3.3 Domino 6 anti-spam configuration	35
3.3.1 Server configuration features	36
3.3.2 User configuration features	37
3.4 Common problems and solutions	37
Chapter 4. Domino 6 Server anti-spam features	41
4.1 How to detect spam	42
4.1.1 Examining the message properties	42
4.1.2 Separating legitimate e-mail from spam based on content	43
4.2 Controlling connections from spammers	44
4.2.1 DNS Blacklist filters	44
4.2.2 Inbound Intended Recipients Controls	48
4.2.3 Disable routing mail to groups	51
4.2.4 Inbound connection controls	53
4.2.5 Inbound sender controls	54
4.3 Controlling delivery of spam	57
4.3.1 Server mail rules	57
4.4 Controlling use of your server as a relay	66
4.4.1 Inbound relay controls	66
4.4.2 Inbound relay enforcement	71
4.5 Protecting your Domino server from active address harvesting attacks	74
4.5.1 SMTP harvesting attacks	74
4.5.2 Spam mail bombing	74
4.5.3 Direct SMTP RCPT TO harvesting	74
4.5.4 Defending against active attacks	75
Chapter 5. Using mail file rules to prevent spam	77
5.1 Distinguishing between spam and legitimate e-mail	78
5.2 Mail file rules	80
5.2.1 Setting up mail file rules	80
5.2.2 Developing anti-spam mail file rules	83
5.2.3 Viewing mail rules and the evaluation sequence	89
5.2.4 Monitoring mail file rules	90
Chapter 6. Third party anti-spam products	93
6.1 Anti-spam products for Notes and Domino	94
6.1.1 spamJam for Lotus Notes and Domino	94
6.1.2 SpamEraser for Lotus Notes and Domino 6	97
6.1.3 iQ.Suite	100
6.1.4 ScanMail for Lotus Notes with eManager	101
6.1.5 XM SpamStop	104
6.1.6 Other anti-spam products for Notes and Domino	106
6.2 Anti-spam server and gateway products and services	106
6.2.1 BrightMail Anti-Spam 4.0 from BrightMail, Inc.	106
6.2.2 ActiveState PureMessage	107
6.2.3 Trend Micro Inc. products	109
6.2.4 Other anti-spam server or gateway products and services	110
Related publications	111
IBM Redbooks	111
Referenced Web sites	111
How to get IBM Redbooks	112
IBM Redbooks collections	112
Index	113

IBM AH0QXML User Guide - Page 17

spammer can create. They can deliberately send empty attachments, bad, headers, looping addresses

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