ngrep

Filter network traffic packets using regular expressions. More information: https://github.com/jpr5/ngrep.

• Capture traffic of all interfaces:
  ngrep -d any
• Capture traffic of a specific interface:
  ngrep -d {{eth0}}
• Capture traffic crossing port 22 of interface eth0:
  ngrep -d {{eth0}} port {{22}}
• Capture traffic from or to a host:
  ngrep host {{www.example.com}}
• Filter keyword 'User-Agent:' of interface eth0:
  ngrep -d {{eth0}} '{{User-Agent:}}'