Arpwatch

{{Short description|Computer networking software tool}}

{{Infobox software

| name = arpwatch

| logo =

| screenshot =

| caption =

| author = Craig Leres

| developer = Lawrence Berkeley National Laboratory Network Research Group

| released = v1.0 Tue Jun 16 3:05:31 PDT 1992

| latest release version = 3.3

| latest release date = {{release date and age|2022|03|26}}

| programming language = C

| operating system = Cross-platform

| platform =

| language = English

| genre = Computer security

| license = 3-clause BSD source with autoconf parts under GNU General Public License

| website = {{URL|ee.lbl.gov}}

}}

{{lowercase|title=arpwatch}}

arpwatch is a computer software tool for monitoring Address Resolution Protocol traffic on a computer network.{{cite web | url=http://linux.die.net/man/8/arpwatch | title=arpwatch(8) manual page | accessdate=2015-01-07}} 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.

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.