How to use NOTIFY

[Jim Reid]

>>>>> "shaun" == root  <shaun at skillin.com> writes:

    shaun> I've recently set up DNS on a linux box as a master.  My
    shaun> old master ( a NT machine) is now secondary.  The only
    shaun> examples I've seen for using the notify statement have been
    shaun> "notify no".  How do I use notify if I want to tell my
    shaun> secondary when updates have occurred.  They're not in sync
    shaun> now, after restarting both of them.  It seems as if the new
    shaun> info isn't being pushed to the secondary, or pulled from
    shaun> the master, and I'm not sure who's job that is.  Any help
    shaun> is, of course, very appreciated.

NOTIFY "just works". When the master server loads a new copy of the
zone it sends NOTIFY messages to the NS records listed in that zone
file. [Unless of course you turn off this mechanism with a "notify no"
clause in named.conf. BTW, an also-notify clause can be used to send
NOTIFY messages to other name servers not listed in the NS records.]

You say that the master and slave (secondary) servers are not in sync
with each other after restarting both of them. This means there is a
deeper and more serious problem with those servers that has nothing to
do with NOTIFY. There are several explanations:

[1] The master is not authoritative for the zone because of errors in
the zone file. This prevents slaves from taking a copy of the zone
with a zone transfer. If this has happened, there will be error
messages in the master server's logs.

[2] The slave server(s) have been misconfigured to check the wrong
name server, so they never consult the zone's master server.

[3] There is a connectivity or routing problem which prevents zone
transfers or other DNS traffic between the master and slave servers.

[4] The master server has been configured to refuse zone transfers
from certain IP addresses, one of which happens to be the address of
the slave server

These problems can be traced by checking the name servers logs and by
running things like dig or named-xfer to try zone transfers by hand
between the master and slave servers.

PS: It's the job of the slave server to synchronise its copy of the
zone with whatever is on the master name server. However if it can't
do that, it doesn't mean the reason for the problem lies with the
slave server.

PPS: The Microsoft name server handles the NOTIFY protocol just fine,
so you shouldn't be looking for implementation or interoperability
problems there.