Source Ports in ARF Reports
draft-kucherawy-marf-source-ports-03

Abstract

This document defines an additional header field for use in Abuse Reporting Format reports to permit the identification of the source port of the connection involved in an abuse incident.

This document updates RFC5965 and RFC6591.

Status of this Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on November 06, 2012.

Copyright Notice

Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 2. Keywords
• 3. Source-Port Field Definition
• 4. Time Accuracy
• 5. IANA Considerations
• 6. Security Considerations
• 7. References
• 7.1. Normative References
• 7.2. Informative References
• Appendix A. Acknowledgements
• Authors' Addresses

1. Introduction

[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 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.

2. Keywords

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].

3. Source-Port Field Definition

A new ARF header field called "Source-Port" is defined. When present in a report, it MUST contain the TCP source port matching the "Source-IP" field in the same report, thereby describing completely the origin of the abuse incident.

  source-port = "Source-Port:" [CFWS] 1*DIGIT [CFWS] CRLF
			

Per, [ABNF], the formal syntax is:

"CFWS" is imported from [MAIL].

When any report is generated that includes the "Source-IP" reporting field (see Section 3.2 of [ARF]), this field SHOULD also be present, unless the port number is unavailable.

Use of this field is RECOMMENED for reports generated per [AUTHFAILURE-REPORT] (see Section 3.1 of that document).

4. Time Accuracy

[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].

5. IANA Considerations

IANA is requested to add the following entry to the Feedback Report Header Fields registry:

Field Name:

Source-Port

Description:

TCP source port from which the reported connection originated

Multiple Appearances:

No

Related Feedback-Type:

any

Reference:

[this document]

Status:

current

6. Security Considerations

This extension introduces no new security considerations not already covered in [ARF].

Some security considerations related to the general topic of source port logging can be found in [LOG].

7. References

7.1. Normative References

7.2. Informative References

Appendix A. Acknowledgements

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