- play_arrow Overview
- play_arrow Overview
- J-Web User Interface for EX Series Switches Overview
- J-Web Interface—Application Package
- Understanding J-Web User Interface Sessions
- Dashboard for EX Series Switches
- Understanding J-Web Configuration Tools
- Understand Alarm Types and Severity Levels on EX Series Switches
- Using the Commit Options to Commit Configuration Changes (J-Web Procedure)
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- play_arrow Configuration
- play_arrow Starting J-Web
- play_arrow J-Web Configuration Tools
- play_arrow System Basics Configuration
- Connecting and Configuring an EX Series Switch (J-Web Procedure)
- Configuring Date and Time for the EX Series Switch (J-Web Procedure)
- Configuring System Identity for an EX Series Switch (J-Web Procedure)
- Configuring Management Access for the EX Series Switch (J-Web Procedure)
- Generating SSL Certificates to Be Used for Secure Web Access (EX Series Switch)
- Rebooting or Halting the EX Series Switch (J-Web Procedure)
- play_arrow Class of Service Configuration
- Defining CoS Drop Profiles (J-Web Procedure)
- Defining CoS Classifiers (J-Web Procedure)
- Defining CoS Code-Point Aliases (J-Web Procedure)
- Assigning CoS Components to Interfaces (J-Web Procedure)
- Defining CoS Forwarding Classes (J-Web Procedure)
- Defining CoS Rewrite Rules (J-Web Procedure)
- Defining CoS Schedulers (J-Web Procedure)
- Defining CoS Scheduler Maps (J-Web Procedure)
- play_arrow Security and Management Configuration
- play_arrow Routing Policies and Packet Filtering Configuration
- play_arrow Ethernet Switching Configuration
- play_arrow Interfaces
- play_arrow Configuring Services
- play_arrow Configuring Layer 3 Protocols
- play_arrow Configuring Real-Time Performance Monitoring
- play_arrow Software Installation and Upgrades
- play_arrow Configuration, Files, Users, Licenses, and Product Registration
- Managing Configuration Files Through the Configuration History (J-Web Procedure)
- Setting or Deleting the Rescue Configuration (J-Web Procedure)
- Uploading a Configuration File (J-Web Procedure)
- Managing Log, Temporary, and Crash Files on the Switch (J-Web Procedure)
- Managing Users (J-Web Procedure)
- Managing Licenses for the EX Series Switch (J-Web Procedure)
- Registering the EX Series Switch with the J-Web Interface
- Generating Support Information Reports for EX Series Switches Using the J-Web Interface
- play_arrow Virtual Chassis Configuration
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- play_arrow Administration
- play_arrow Software, Files, Licenses, Logs
- Uploading a Configuration File (J-Web Procedure)
- Managing Configuration Files Through the Configuration History (J-Web Procedure)
- Setting or Deleting the Rescue Configuration (J-Web Procedure)
- Updating J-Web Interface on EX Series Switches (J-Web Procedure)
- Upgrading Junos OS on EX Series Switches (J-Web Procedure)
- Managing Licenses for the EX Series Switch (J-Web Procedure)
- Rebooting or Halting the EX Series Switch (J-Web Procedure)
- Managing Log, Temporary, and Crash Files on the Switch (J-Web Procedure)
- Registering the EX Series Switch with the J-Web Interface
- Generating Support Information Reports for EX Series Switches Using the J-Web Interface
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- play_arrow Troubleshooting
- play_arrow Troubleshooting Task
- play_arrow FAQ
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Monitoring Switch Control Traffic
Purpose
This topic applies only to the J-Web Application package.
Use the packet capture feature when you need to quickly capture and analyze switch control traffic on a switch. The packet capture feature allows you to capture traffic destined for or originating from the Routing Engine.
Action
To use the packet capture feature in the J-Web interface, select Troubleshoot > Packet Capture.
To use the packet capture feature in the CLI, enter the following CLI command:
monitor traffic
Meaning
You can use the packet capture feature to compose expressions with various matching criteria to specify the packets that you want to capture. You can decode and view the captured packets in the J-Web interface as they are captured. The packet capture feature does not capture transient traffic.
Field | Function | Your Action |
|---|---|---|
Interface | Specifies the interface on which the packets are captured. If you select default, packets on the Ethernet management port 0, are captured. | From the list, select an interface—for example, ge-0/0/0. |
Detail level | Specifies the extent of details to be displayed for the packet headers.
| From the list, select Detail. |
Packets | Specifies the number of packets to be captured. Values range from 1 to 1000. Default is 10. Packet capture stops capturing packets after this number is reached. | From the list, select the number of packets to be captured—for example, 10. |
Addresses | Specifies the addresses to be matched for capturing the packets using a combination of the following parameters:
You can add multiple entries to refine the match criteria for addresses. | Select address-matching criteria. For example:
|
Protocols | Matches the protocol for which packets are captured. You can choose to capture TCP, UDP, or ICMP packets or a combination of TCP, UDP, and ICMP packets. | From the list, select a protocol—for example, tcp. |
Ports | Matches packet headers containing the specified source or destination TCP or UDP port number or port name. | Select a direction and a port. For example:
|
Advanced Options | ||
Absolute TCP Sequence | Specifies that absolute TCP sequence numbers are to be displayed for the packet headers. | To display absolute TCP sequence numbers in the packet headers, select this check box. |
Layer 2 Headers | Specifies that link-layer packet headers are to be displayed. | To include link-layer packet headers while capturing packets, select this check box. |
Non-Promiscuous | Specifies not to place the interface in promiscuous mode, so that the interface reads only packets addressed to it. In promiscuous mode, the interface reads every packet that reaches it. | To read all packets that reach the interface, select this check box. |
Display Hex | Specifies that packet headers, except link-layer headers, are to be displayed in hexadecimal format. | To display the packet headers in hexadecimal format, select this check box. |
Display ASCII and Hex | Specifies that packet headers are to be displayed in hexadecimal and ASCII format. | To display the packet headers in ASCII and hexadecimal formats, select this check box. |
Header Expression | Specifies the match condition for the packets to be captured. The match conditions you specify for Addresses, Protocols, and Ports are displayed in expression format in this field. | You can enter match conditions directly in this field in expression format or modify the expression composed from the match conditions you specified for Addresses, Protocols, and Ports. If you change the match conditions specified for Addresses, Protocols, and Ports again, packet capture overwrites your changes with the new match conditions. |
Packet Size | Specifies the number of bytes to be displayed for each packet. If a packet header exceeds this size, the display is truncated for the packet header. The default value is 96 bytes. | Type the number of bytes you want to capture for each packet header—for example, 256. |
Don't Resolve Addresses | Specifies that IP addresses are not to be resolved into hostnames in the packet headers displayed. | To prevent packet capture from resolving IP addresses to hostnames, select this check box. |
No Timestamp | Suppresses the display of packet header timestamps. | To stop displaying timestamps in the captured packet headers, select this check box. |
Write Packet Capture File | Writes the captured packets to a file in PCAP format in /var/tmp. The files are named with the prefix jweb-pcap and the extension .pcap. If you select this option, the decoded packet headers are not displayed on the packet capture page. | To decode and display the packet headers on the J-Web page, clear this check box. |
