PCAP Capture File Format
draft-gharris-opsawg-pcap-01
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
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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.
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Copyright Notice
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document authors. All rights reserved.
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Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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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.
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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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