avahi-dnsconfd.action is the action script that is called whenever a new unicast DNS server is found or removed by avahi-dnsconfd. The default script as shipped with avahi patches /etc/resolv.conf to reflect the changed unicast DNS server configuration.
argv Contains the character "+" if the DNS server is new, "-" when it shall be removed from the DNS server list.
argv The IP address of the DNS server.
argv Numerical network interface number this DNS server was found on.
argv Numerical protocol number this DNS server was found on. (usually 2 for IPv4 and 10 for IPv6)
AVAHI_INTERFACE Contains the textual interface name the corresponds with argv. (e.g. "eth0")
AVAHI_INTERFACE_DNS_SERVERS Contains a list of all DNS servers that avahi-dnsconfd found on the interface $AVAHI_INTERFACE, separated by spaces.
AVAHI_DNS_SERVERS Contains a list of all DNS server that avahi-dnsconfd found on all interfaces, separated by spaces.
The Avahi Developers <avahi (at) lists (dot) freedesktop (dot) org>; Avahi is available from http://avahi.org/