Arpsnmp has the same database features of arpwatch but relies on an external agent to collect the arp data.
This distribution contains a script, arpfetch, that uses snmpwalk from the CMU SNMP package.
This is a forked version of the original arpwatch licensed under the BSD license (afaik).
I think it's okay that I release it with my changes under GPL.
Since the 802.1Q tag inserts 32 bits between the MAC source address and the original Ethernet type field (0x806), the ARP data fields are not where arpwatch expects to see them.
I would patch this myself except that I'm not sure what the correct fix should be.
ARPWatch monitors MAC adresses on your network and writes them into a file, last know timestamp and change notification is included.
This package is available from: ftp://cmu.edu/pub/snmp-dist/cmu-snmp*gz It should be trivial to adapt the output of any snmp query program for use with arpsnmp.
The ethernet vendor codes in is only current at the time the last arpwatch release was assembled.
Arpwatch keeps track for ethernet/ip address pairings.
It syslogs activity and reports certain changes via email.