Internet Engineering Task Force (IETF) R. Clayton Request for Comments: 6692 University of Cambridge Updates: 6591 M. Kucherawy Category: Standards Track Cloudmark, Inc. ISSN: 2070-1721 July 2012
Source Ports in Abuse Reporting Format (ARF) Reports
Abstract
This document defines an additional header field for use in Abuse Reporting Format (ARF) reports to permit the identification of the source port of the connection involved in an abuse incident.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6692.
Copyright Notice
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[ARF] defined the Abuse Reporting Format, an extensible message format for Email Feedback Reports. These reports are used to report incidents of email abuse. ARF was extended by [AUTHFAILURE-REPORT] to enable the reporting of email authentication failures. These specifications provided for the source IP address to be included in a report. As explained in [LOG], the deployment of IP address sharing techniques requires the source port values to be included in reports if unambiguous identification of the origin of abuse is to be achieved.
This document defines an ARF reporting field to contain this information and provides guidance for its use.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [KEYWORDS].
A new ARF header field called "Source-Port" is defined. When present in a report, it MUST contain the client port of the TCP connection from which the reported message originated, corresponding to the "Source-IP" field that contains the client address of that same connection, thereby describing completely the origin of the abuse incident.
"CFWS", which represents email-style comments or folding white space, is imported from [MAIL].
When any report is generated that includes the "Source-IP" field (see Section 3.2 of [ARF]), this field SHOULD also be present, unless the port number is unavailable.
Use of this field is RECOMMENDED for reports generated per [AUTHFAILURE-REPORT] (see Section 3.1 of that document).
[LOG] underscores the importance of accurate clocks when generating reports that include source port information because of the fact that source ports can be recycled very quickly in Internet Service Provider environments. The same considerations described there apply here.
Report generators that include an Arrival-Date report field MAY choose to express the value of that date in Universal Coordinated Time (UTC) to enable simpler correlation with local records at sites that are following the provisions of [LOG].
The authors wish to acknowledge the following for their review and constructive criticism of this proposal: Steve Atkins, Scott Kitterman, John Levine, and Doug Otis.
The idea for this work originated within the Messaging Anti-Abuse Working Group (MAAWG).
Authors' Addresses
Richard Clayton University of Cambridge Computer Laboratory JJ Thomson Avenue Cambridge CB3 0FD United Kingdom