PCAP Capture File Format
draft-gharris-opsawg-pcap-01

Document Type Active Internet-Draft (individual)
Authors Guy Harris  , Michael Richardson 
Last updated 2020-12-21
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Network Working Group                                     G. Harris, Ed.
Internet-Draft                                                          
Intended status: Informational                             M. Richardson
Expires: 24 June 2021                                          Sandelman
                                                        21 December 2020

                        PCAP Capture File Format
                      draft-gharris-opsawg-pcap-01

Abstract

   This document describes the format used by the libpcap library to
   record captured packets to a file.  Programs using the libpcap
   library to read and write those files, and thus reading and writing
   files in that format, include tcpdump.

Discussion Venues

   This note is to be removed before publishing as an RFC.

   Discussion of this document takes place on the OPSAWG Working Group
   mailing list (opsawg@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/opsawg/.

   Source for this draft and an issue tracker can be found at
   https://github.com/pcapng/pcapng.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 24 June 2021.

Harris & Richardson       Expires 24 June 2021                  [Page 1]
Internet-Draft                    pcap                     December 2020

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  General File Structure  . . . . . . . . . . . . . . . . . . .   3
   4.  File Header . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Packet Record . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Recommended File Name Extension: .pcap  . . . . . . . . . . .   7
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     8.1.  LinkType Registry . . . . . . . . . . . . . . . . . . . .   7
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  28
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  28
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  28
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  28
     11.2.  Informative References . . . . . . . . . . . . . . . . .  28
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  28

1.  Introduction

   In the late 1980's, Van Jacobson, Steve McCanne, and others at the
   Network Research Group at Lawrence Berkeley National Laboratory
   developed the tcpdump program to capture and dissect network traces.
   The code to capture traffic, using low-level mechanisms in various
   operating systems, and to read and write network traces to a file was
   later put into a library named libpcap.

   This document describes the format used by tcpdump, and other
   programs using libpcap, to read and write network traces.

Harris & Richardson       Expires 24 June 2021                  [Page 2]
Internet-Draft                    pcap                     December 2020

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  General File Structure

   A capture file begins with a File Header, followed by zero or more
   Packet Records, one per packet.

   All fields in the File Header and in Packet Records will always be
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