ngrep – grep applied to the network layer

ngrep is like grep applied to the network layer.

It’s a PCAP-based tool that allows you to specify an extended regular or hexadecimal expression to match against data payloads of packets. It understands many kinds of protocols, including IPv4/6, TCP, UDP, ICMPv4/6, IGMP and Raw, across a wide variety of interface types, and understands BPF filter logic in the same fashion as more common packet sniffing tools, such as tcpdump and snoop.

ngrep is free and open source software.

Features include:

• Supports Berkeley Packet Filter (BPF) logic to select network sources or destinations or protocols, and also allows matching patterns or regular expressions in the data payload of packets using GNU grep syntax, showing packet data in a human-friendly way.
• Look for a regular expression in the payload of the packet, and show the matching packets on a screen or console.
• Debug plain text protocols interactions like HTTP, SMTP, FTP, DNS, among others, or to search for a specific string or pattern, using a grep regular expression syntax.
• Capture traffic on the wire and store pcap dump files, or to read files generated by other sniffer applications, like tcpdump, or Wireshark.

Website: github.com/jpr5/ngrep
Support:
Developer: Jordan Ritter
License: BSD-style License

ngrep is written in C. Learn C with our recommended free books and free tutorials.

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