Re: Migrating to new ISP

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"Paulo Faustino" <paulofaustino@xxxxxxx> wrote in message
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"Herb Martin" <news@xxxxxxxxxxxxxx> wrote in message
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"Paulo Faustino" <paulofaustino@xxxxxxx> wrote in message
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"Herb Martin" <news@xxxxxxxxxxxxxx> wrote in message
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"Barry" <bazagee@xxxxxxxxxxx> wrote in message
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Hi all,

I'm looking for advice on moving to a new ISP in a smooth manner with
little or no down time to our public websites, MX etc.

Change the TTL to something small at LEAST one full TTL period ahead of
the
change.

E.g., if you TTL is 1 day, then at least a day ahead, change it to 5
minutes or
some such.

My concern is how to do this with Win2k DNS services. I will have new
IP's mapped to the Nics of our servers in advance and have contacted
our Domain registrant to see if we can add multiple ip's to our
nameserver records. I was hoping to be able to propagate downstream
routers before the phyisical changeover. We have two public facing DNS
server, Primary and Secondary zones.

Can this be done or what is the better way of approaching this?
TIA

TTL settings are the key and it doesn't matter if it is Windows DNS or
some
(unknown) ISP/Registrar DNS server (e.g., BIND).

BTW, most companies should NOT be running their own public DNS but
should be using the REGSTRAR provided DNS Servers so you might wish
to consider this before performing this move and just use that instead.


Why you advice so strongly for most of the companies to do not run their
own dns services?

Because the DNS for the PUBLIC resolution should be completely separate
from
the private, their is a business rule (not really enforced) that public
DNS must be
at least two machines (and a lot of these people don't even have one that
is
separate), and because it is just something else that might be
compromised or
use up cycles on a web server etc.

The Registrars already provide a fault tolerant, battery backed up, 24/7
supported
DNS service in almost all cases (for free), and a nice GUI-Web interface
for you
to manage it yourself.

The exceptions are (possibly) those companies who have a large Internet
presense,
with many Internet facing records and/or frequent changes, plus their own
dedicated
staff who manage little or nothing else.

Also, the issue that many ISP will DISALLOW your public DNS server(s)
from
doing recursion which effectively enforces the strong suggestion that the
internal
and external DNS servers should be separate machines.

It is really a no brainer. Let the registrar do it (not the ISP either
in almost all
cases.)



Good point, although i guess alot prefer to run the domains on their
servers for speed and utmost control. And in some cases GUI-Web interface
that is made available do not cover all your needs.

In the FEW cases where the "GuiWeb interface" doesn't cover you needs you
likely fall outside the scope of what I mean when I say "except for those
companies
with a large web presence".

For simple setups it really is a no brainer and those wanting "more control"
are
usually the ones asking naive DNS questions which prove that their having
"more
control" is not such a good idea.

BTW, my own PUBLIC DNS is largely provided by the registrar (in almost all
cases except for one really odd historical exception) and no one ever
accuess me
of not understanding DNS. <grin>




.

Relevant Pages

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