Flags used here:

• -i interface: use the interface network interface.
• -s snaplen: read snaplen bytes of data from each packet rather than the default 262144.
• -n: don't convert addresses (i.e., host addresses, port numbers, etc.) to names.
• -Z user: run as user instead of root.
• -C file_size: write maximum file_size bytes to a single file.
• -W filecount: limit the number of files created to filecount.
• -w file: write output to file.
• -f: print IPv4 addresses numerically rather than symbolically.

With &>/dev/null we redirect both the standard output and the standard error to /dev/null.

Requires tcpdump.