Juniper Networks J-Series manual Configuring Packet Capture, Packet Capture Terms

Chapter 13

Configuring Packet Capture

Packet capture is a tool that helps you to analyze network traffic and troubleshoot network problems. On a J-series Services Router, the packet capture tool captures real-time data packets traveling over the network, for monitoring and logging.

Packets are captured as binary data, without modification. You can read the packet information offline with a packet analyzer such as Ethereal or tcpdump.

If you need to quickly capture packets destined for or originating from the Routing Engine and analyze them online, you can use the J-Web packet capture diagnostic tool. For more information, see “Capturing and Viewing Packets with the J-Web Interface” on page 226.

NOTE: J-series Services Routers can capture IPv4 packets only. The packet capture tool does not support IPv6 packet capture.

You can use either the J-Web configuration editor or CLI configuration editor to configure packet capture. For more information about packet capture, see the JUNOS Policy Framework Configuration Guide.

This chapter contains the following topics.

■Packet Capture Terms on page 253

■Packet Capture Overview on page 254

■Before You Begin on page 257

■Configuring Packet Capture with a Configuration Editor on page 257

■Changing Encapsulation on Interfaces with Packet Capture Configured on page 262

■Verifying Packet Capture on page 263

Packet Capture Terms

Before configuring packet capture on a Services Router, become familiar with the terms defined in Table 133 on page 254.

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