Microsoft KB Archive/244346

= XCON: Routing Restrictions Do Not Work with % Addresses RFC 1123 5.2.16 =

Article ID: 244346

Article Last Modified on 10/28/2006

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APPLIES TO


 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q244346



SYMPTOMS
The source routing that is specified in Request for Comments (RFC) 1123 5.2.16 allows for addresses to be encapsulated in the recipient part of a Simple Mail Transfer Protocol (SMTP) address. This enables a person to send an e-mail address to an SMTP host, and the host then parses the address and reroutes the message to the intended recipient.

An Internet Mail Service that is set up to receive only messages that are destined for the SMTP domain name processes source routing messages completely before it sends back a non-delivery report (NDR).

Messages are completely processed, even if routing restrictions are specified and a user uses the source routing that is specified in RFC 1123 5.2.16. This may be the tactic that is used for a denial of service attack on an Internet Mail Service.



MORE INFORMATION
This behavior is by design.

Additional query words: RFC 1123 5.2.16, source routing, IMS

Keywords: kbprb KB244346

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