Arpwatch

arpwatch is a computer software tool for monitoring Address Resolution Protocol traffic on a computer network.^[1] It generates a log of observed pairing of IP addresses with MAC addresses along with a timestamp when the pairing appeared on the network. It also has the option of sending an email to an administrator when a pairing changes or is added.

arpwatch
Original author(s)	Craig Leres
Developer(s)	Lawrence Berkeley National Laboratory Network Research Group
Initial release	v1.0 Tue Jun 16 3:05:31 PDT 1992
Stable release	3.3 / March 26, 2022; 3 years ago (2022-03-26)
Written in	C
Operating system	Cross-platform
Available in	English
Type	Computer security
License	3-clause BSD source with autoconf parts under GNU General Public License
Website	ee.lbl.gov

Network administrators monitor ARP activity to detect ARP spoofing, network flip-flops, changed and new stations and address reuse.

arpwatch was developed by Lawrence Berkeley National Laboratory, Network Research Group, as open-source software and is released under the BSD license.

See also

• ArpON
• arping
• Ettercap

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