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request packet-capture start

date_range 09-Dec-23

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Syntax

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request packet-capture start
<bidirectional bidirectional>
<capture-file capture-file>
<count count>
<destination-port destination-port>
<destination-prefix destination-prefix>
<interface interface>
<maximum-capture-size maximum-capture-size>
<protocol protocol-number>
<size size>
<source-port source-port>
<source-prefix source-prefix>

Description

Captures packet information from the operational mode. You can execute the packet capture from the operational mode with minimal impact to the production system without committing the configurations. You can define the packet filter to trace the type of traffic based on your requirement.

You can request for only one packet capture at a time, and you need to stop each packet capture request before you give an another packet capture request. For each packet capture request, you need to give the respective show command to view the output.

In chassis cluster mode, you must request operational mode packet capture from the primary node. Operational mode packet capture does not function when executed from the secondary node.

Options

bidirectional	Allows to collect bidirectional information.
`capture-file`	Name of the capture file. It generates a pcap file, which can support Wireshark by adding the suffix ‘.pcap’.
count	Number of packets to capture. Range: 10 through 1000000 Default: 100
destination-port	TCP/UDP destination port.
destination-prefix	Destination IPv4/IPv6 address prefix to filter the packets.
interface	Name of the logical interface.
`maximum-capture-size`	The maximum size of packet capture. The packet truncates if the capture size is more than the specified capture size. Range: 68 through 10000 Default: 1514
`protocol-number`	Numeric protocol value. Range: 0 through 255 Default: 0
`size`	The maximum size of packet capture file. Range: 10240 through 1073741824 Default: 50M
source-port	TCP/UDP source port.
source-prefix	Source IPv4/IPv6 address prefix to filter the packets.

Required Privilege Level

view

Output Fields

Table 1 lists the output fields for the request packet-capture start command. Output fields are listed in the approximate order in which they appear.

Table 1: request packet-capture start Output Fields
Field Name	Field Description
`packet capture is running`	Status of the packet capture session: `0`: No packet capture is performing. `1`: Packet capture is performing.
`counter of packet capture`	Number of packets captured.
`packet capture capture-file name`	Name, location, size and capture length of the packet capture file.
`Flag`	Decimal value corresponding to the type of filter configured. Convert this value to binary or hexadecimal format such as: 0x000 (No filters) 0x001 (Source IP) 0x002 (Destination IP) 0x004 (Protocol) 0x008 (Source port) 0x010 (Destination port) 0x040 (Filter is valid) 0x200 (IPv6 Source IP) 0x400 (IPv6 Destination IP) 0x800 (Interface) For example if the flag value is `72`, convert it to binary or hexadecimal format: 72 = 0x48 0x040 (Filter is valid) 0x008 (Source port) This means that the filter is valid and only configured with the filter source port.
`Source`	Source IPv4/IPv6 address.
`Destination`	Destination IPv4/IPv6 address.
`Interface`	Name of the logical interface.
`bidirectional`	Status of the bidirectional keyword configuration: `0`: Not configured. `1`: Configured.
`Protocol`	Numeric protocol value.
`rotate`	Number of capture files.
`snap_len`	The maximum packet capture size.
`ifl`	If index value of interface.

Sample Output

Packet capture using protocol, destination port, destination prefix, and bidirectional options
Packet capture using interface
Packet capture using source prefix
Packet capture using source port
Packet capture using protocol

Packet capture using protocol, destination port, destination prefix, and bidirectional options

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root@host> request packet-capture start protocol 17 destination-port 53 destination-prefix 203.0.113.0 bidirectional
{primary:node1}
root@host> show packet-capture status
    packet capture is running: 1
    counter of packet capture: 100
    packet capture capture-file name: /var/log/packet-capture.pcap size: 52428800 rotate: 0 snap_len: 1514
  bidirectional: 1
    Flag: 86 Protocol: udp
    Source: 0.0.0.0 0.0.0.0 (port 0~65535)
    Destination: 203.0.113.0 255.255.255.255 (port 53~53)
    Interface: None ifl: 0
     Flag: 77 Protocol: udp
    Source: 203.0.113.0 255.255.255.255 (port 53~53)
    Destination: 0.0.0.0 0.0.0.0 (port 0~65535)
    Interface: None ifl: 0

Packet capture using interface

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user@host> request packet-capture start capture-file cli-e2e interface xe-1/0/2.0
user@host> show packet-capture status
packet capture is running: 1 
    counter of packet capture: 100
    packet capture capture-file name: /var/log/cli-e2e.pcap size: 52428800 rotate: 0 snap_len: 1514 
  bidirectional: 0
    Flag: 2112 
    Source: 0.0.0.0 0.0.0.0 (port 0~65535)
    Destination: 0.0.0.0 0.0.0.0 (port 0~65535)
    Interface: xe-1/0/2.0 ifl: 68

Packet capture using source prefix

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user@host> request packet-capture start capture-file cli-e2e source-prefix 192.0.2.0
user@host> show packet-capture status
packet capture is running: 1 
counter of packet capture: 100 
packet capture capture-file name: /var/log/cli-e2e.pcap size: 52428800 rotate: 0 snap_len: 1514 
bidirectional: 0 
Flag: 65 
Source: 192.0.2.0.2 255.255.255.255 (port 0~65535) 
Destination: 0.0.0.0 0.0.0.0 (port 0~65535) 
Interface: None ifl: 0 

Packet capture using source port

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user@host> request packet-capture start capture-file cli-e2e count 100 source-port telnet
user@host> show packet-capture status
packet capture is running: 1 
counter of packet capture: 100 
packet capture capture-file name: /var/log/cli-e2e.pcap size: 52428800 rotate: 0 snap_len: 1514 
bidirectional: 0 
Flag: 72 
Source: 0.0.0.0 0.0.0.0 (port 23~23) 
Destination: 0.0.0.0 0.0.0.0 (port 0~65535) 
Interface: None ifl: 0 

Packet capture using protocol

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user@host> request packet-capture start protocol 6
user@host> show packet-capture status
packet capture is running: 1 
counter of packet capture: 100 packet 
capture capture-file name: /var/log/packet-capture.pcap size: 52428800 rotate: 0 snap_len: 1514 
bidirectional: 0 
Flag: 68 
Protocol: tcp 
Source: 0.0.0.0 0.0.0.0 (port 0~65535) 
Destination: 0.0.0.0 0.0.0.0 (port 0~65535) 
Interface: None ifl: 0 

Release Information

Statement introduced in Junos OS Release 19.3R1.

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Junos CLI Reference

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request packet-capture start

Syntax

Description

Options

Required Privilege Level

Output Fields

Sample Output

Packet capture using protocol, destination port, destination prefix, and bidirectional options

Packet capture using interface

Packet capture using source prefix

Packet capture using source port

Packet capture using protocol

Release Information

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Junos CLI Reference

ON THIS PAGE

request packet-capture start

Syntax

Description

Options

Required Privilege Level

Output Fields

Sample Output

Packet capture using protocol, destination port, destination prefix, and bidirectional options

Packet capture using interface

Packet capture using source prefix

Packet capture using source port

Packet capture using protocol

Release Information

Related Documentation

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