Nameserver TTL's
Mark_Andrews at isc.org
Mark_Andrews at isc.org
Sun Jun 20 03:51:42 UTC 1999
> Hello,
>
> We all know that the TTL's in DNS don't always take
> effect when we expect them due to web caching and policies
> imposed by different providers, but I am not quite sure how
> the following is happening:
>
> A domain "etown.com", was recently switched between providers.
> The old providers nameservers were "ns1.methodfive.com" and
> "ns2.methodfive.com" which had TTL values of 2 Days. The
> new providers nameservers are "jedi.colo.jalan.com" and
> "keats.jalan.com" which has TTL values of 1HR.
>
> It's been almost 7 days since the changes were put into effect
> on the root nameservers, yet there are still provider nameservers
> out there showing the authoritive nameservers for the domain to be
> the methodfive ones.
>
> In particular, ns1.ironlight.com, shows that it just reloaded it's
> nameservers and that the TTL for the methodfive servers is again
> near two days.
>
> How can this be happening?
> Any ideas?
>
> Thanks,
> Matt
> --
> Matthew Marlowe http://www.jalan.com/ (p) 909.799.3805
> mmarlowe at jalan.com Jalan Network Services (f) 909.799.3285
> "Quality Web Hosting, Network, Linux, and Solaris Consulting"
>
>
Make the old servers secondaries or turn them off. Having two
sets of servers claiming to be authorative for the one zone
is never a good idea.
The correct way to change servers is to make the old servers
secondaries until the all cached records refering to them
have timed out then decommission. Just changing the old master
to be a slave should cause the new zone contents to transfer
to all the old secondaries.
Just changing the delegation is not guaranteed to stop sites
re-learning old delegations if they are not made secondaries of
the new contents.
RFC 1034/1035 has always allowed the set of authorative servers
to be sent in the authority section regardless of whether the
answer is authorative or not.
Mark
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka at isc.org
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