Additional Reading

• Internet RFC 821 ( http://www.ietf.org/rfc/rfc0821.txt ) defines the SMTP protocol, and it remains the definitive standard for how SMTP relaying is supposed to work.

• RFC 2552 ( http://www.ietf.org/rfc/rfc2552.txt ) defines the SMTP AUTH extension and explains how it works.

• RFC 2635 describes spam, defines what it is, and explains why people hate it so much. Although this might seem redundant, the RFC s explanation is clear and suitable for end users. It s available from http://www.ietf.org/rfc/rfc2635.txt.

• For more details on the differences between SMTP virtual servers and connectors, see the Exchange Server 2003 Administrator s Companion by Walter J. Glenn and Bill English (Microsoft Press, 2004).

• The Internet Mail Consortium maintains an interesting report on unsolicited bulk e-mail at their Web site ”see UBE: Definitions and Problems at http://www.imc.org/ube-def.html.

• Dr. J rgen Mash maintains a list of RBL lists at http://www.moensted.dk/spam . The list is not 100 percent up to date, but it contains links to more than 500 filtering lists and services. This might be useful if you re considering a perimeter spam-blocking solution.