Chapter 4. Capturing Live Network Data

Table of Contents

4.1. Introduction
4.2. Prerequisites
4.3. Start Capturing
4.4. The "Capture Interfaces" dialog box
4.5. The "Capture Options" dialog box
4.5.1. Capture frame
4.5.2. Capture File(s) frame
4.5.3. Stop Capture... frame
4.5.4. Display Options frame
4.5.5. Name Resolution frame
4.5.6. Buttons
4.6. The "Interface Details" dialog box
4.7. Capture files and file modes
4.8. Link-layer header type
4.9. Filtering while capturing
4.9.1. Automatic Remote Traffic Filtering
4.10. While a Capture is running ...
4.10.1. Stop the running capture
4.10.2. Restart a running capture

4.1. Introduction

Capturing live network data is one of the major features of Wireshark.

The Wireshark capture engine provides the following features:

  • Capture from different kinds of network hardware (Ethernet, Token Ring, ATM, ...).

  • Stop the capture on different triggers like: amount of captured data, captured time, captured number of packets.

  • Simultaneously show decoded packets while Wireshark keeps on capturing.

  • Filter packets, reducing the amount of data to be captured, see Section 4.9, “Filtering while capturing”.

  • Capturing into multiple files while doing a long term capture, and in addition the option to form a ringbuffer of these files, keeping only the last x files, useful for a "very long term" capture, see Section 4.7, “Capture files and file modes”.

The capture engine still lacks the following features:

  • Simultaneous capturing from multiple network interfaces (however, you can start multiple instances of Wireshark and merge capture files later).

  • Stop capturing (or doing some other action), depending on the captured data.