Before I go out on a limb, I wanted to ask those who know more about
this than I do. I added a zone change to my primary server, in this
case, setting the TTL's pretty low, as things were going to move
around a bit in the beginning. Waited a few weeks after adding it.
* The basic thing I am trying to understand, is *when* the slaves get
the change, and what repercussions there are if it is slow.
Here is the zone:
ORIGIN .
$TTL 86400 ; 1 day
example.com IN SOA ns1.hostwizard.com.
scott.hostwizard.com. (
2008112501 ; serial *** I did change
this ***
14400 ; refresh (4 hours)
7200 ; retry (2 hours)
604800 ; expire (1 week)
3600 ; minimum (1 hour)
)
$TTL 3600 ; 1 hour
NS ns1.hostwizard.com.
NS ns1.nacio.com.
A 64.84.37.51
$TTL 300 ; 5 minutes
MX 10 gonepostal.hostwizard.com.
$TTL 3600 ; 1 hour
TXT "v=spf1 ip4:64.84.37.0/26 ?all"
$ORIGIN example.com.
foo A 64.84.37.51
bar A 64.84.37.51
$TTL 300 ; 5 minutes
www A 64.84.37.51
pop A 64.84.37.6
smtp A 64.84.37.6
dig example.com MX
That will give me back the MX you see above. In this case, I am on a
starbucks wifi, so they use whatever NS they are using.
At home, the same command, pointed to openDNS, gives back the new MX
as well.
Now, if I run dig example.com MX @ns1.hostwizard.com I also get the
new MX
Running dig example.com MX @ns1.nacio.com, which is my slave provide
example.com. 188 IN MX 20 mx1.biz.mail.yahoo.com.
example.com. 188 IN MX 30 mx5.biz.mail.yahoo.com.
It took openDNS, all of 6 or 7 minutes to get the change, I am now,
hours later, not seeing the change in my secondary provider. They
also have ns0.nacio.com, ns1.nacio.com, ns2.nacio.com and
ns3.nacio.com, all of which answer stale for this query.
Am I correct, in that, the 300 TTL I set, is correct, and what I
should have done to prepare for a MX change to happen with as little
problem/delay as possible?
What is the setting on a slave that determines when it should see my
change? My logs show the notifies going over, and being accepted.
I also provide a secondary, and to be honest, if I wanted to stall my
secondary from accepting a primary notify, different than the TTL, I
would not even know how to do that.
If the whois servers are listed with myself, and my secondary, and the
secondary is now stale, for hours, what repercussions does this have?
I think, queries that are not cached by the local resolver of a
internet user, go back to whoever is listed in the whois. I am also
pretty sure it does not pick one over the other, I see no way a client
request could pick a primary over a secondary, I believe it happens at
random, almost in a load balanced way, or perhaps it is distance
routed, so the closest is first.
Either way, am I correct in that a secondary, is needed, if it is
there, it must be in sync, as it is pretty evenly used by all clients
requesting data from it, until their local resolver caches it?
Thanks, and as I said, I am just trying to understand this, so I have
the correct date to provide a accurate support request.
--
Scott
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