Q. I would like to know - how do I detect ARP spoofing? I am using Debian Linux.
A. Use arpwatch command to keeps track for ethernet/ip address pairings. It logs message or activity to syslogs and reports certain changes via email.
Arpwatch uses pcap to listen for arp packets on a local ethernet interface.
Install arpwatch
Use apt-get command under Debian / Ubuntu Linux:
# apt-get install arpwatchOR
$ sudo apt-get install arpwatch
You can watch particular interface with command: You will notice syslog entries as follows /var/log/syslog file (or /var/log/message file) when changes are made i.e MAC/IP address pair is changed: Above entry displays new workstation. If changes are made you should see something as follows: You can also use arp -a command to display current ARP table:
arpwatch command examples
# arpwatch -i eth0
# tail -f /var/log/syslogOutput:
Nov 10 15:59:34 debian arpwatch: new station 192.168.1.2 0:17:9a:a:f6:44 eth0
Nov 10 15:59:34 debian arpwatch: changed station 192.168.1.2 0:17:9a:b:f6:f6
(0:17:9a:a:f6:44)
$ arp -arefer : http://www.cyberciti.biz/faq/how-to-detect-arp-spoofing-under-unix-or-linux/