bind NOTIFY protocol

[Jim Reid]

>>>>> "Chuck" == Chuck Scott <chuck at opendesign.com> writes:

    Chuck> I was curious if anyone was familiar with the NOTIFY
    Chuck> protocol and how the master sends out a NOTIFY request to
    Chuck> all the slaves.  Specifically, I am curious on how the
    Chuck> master is able to determine who the slaves are (i.e. NS
    Chuck> records defined in its zone configuration files) or does it
    Chuck> keep record of previously initiated zone-xfers from the
    Chuck> slaves?

NOTIFY messages are sent to the addresses of zone's NS records. A name
server can be configured to send them to other addresses too: see the
also-notify clause in BIND[89]. Keeping track of previous zone xfers
is not wise: how can the server tell the difference between a slave
server's axfr request and some random user just making an axfr with
dig or nslookup? Think of the fun - denial of service attacks - if the
server had to keep track of the source address of every axfr request
it got. RFC1996 will tell you more than you probably want to know
about the NOTIFY protocol.