Works on Cisco ASAs only. Works for site-to-site VPNs only (not SSL or client VPNs).
usage: check_asa_l2lvpn IPADDRESS SNMP_COMMUNITY PEER_IP FRIENDLY_NAME
The FRIENDLY_NAME option is used for the service_description. For example, if FRIENDLY_NAME is set to "salesoffice", the script will return a results for the service_description "VPN-salesoffice".
More info at: http://www.barkingseal.com/2009/08/monitoring-site-to-site-vpns-on-a-cisco-asa/