getpcaps - Linux

Overview

getpcaps is a versatile command-line tool designed to retrieve packets from a network interface in libpcap format. It offers comprehensive filtering capabilities, allowing users to capture specific packets based on various criteria. This tool is invaluable for network monitoring, security analysis, and protocol debugging.

Syntax

getpcaps [-i interface] [-f pcap_file] [-c count] [-s snaplen]
          [-t timeout] [-w filter] [-d] [-v]

Options/Flags

• -i interface: Network interface to capture packets from.
• -f pcap_file: Write packet data to a specified PCAP file.
• -c count: Max number of packets to capture.
• -s snaplen: Maximum number of bytes to capture for each packet.
• -t timeout: Time (in seconds) to capture packets.
• -w filter: Filtering expression using PCAP filter syntax.
• -d: Enable debug mode for detailed logging.
• -v: Display version information.

Examples

Capture 100 packets from eth0 interface:

getpcaps -i eth0 -c 100

Capture packets with source IP 192.168.1.10:

getpcaps -w "ip src 192.168.1.10"

Capture packets with TCP destination port 80:

getpcaps -w "tcp dst port 80"

Capture packets and save them in my_capture.pcap file:

getpcaps -f my_capture.pcap

Common Issues

• Received traffic not matching filters: Ensure filters are correctly specified using the PCAP filter syntax.
• No packets captured: Check if the specified interface is up and receiving traffic.
• File permissions: Ensure you have write permissions to the specified PCAP file.

Integration

Combine with other commands:

• tcpdump -A: Use getpcaps to capture packets and display them in a human-readable format.

getpcaps -i eth0 -c 100 | tcpdump -A

• wireshark -r: Use getpcaps to capture packets and open them in Wireshark for detailed analysis.

getpcaps -f my_capture.pcap & wireshark -r my_capture.pcap

Related Commands

• tcpdump – Command-line packet analyzer
• wireshark – Graphical network protocol analyzer
• dumpcap – Libpcap command-line interface