Migrating to new ISP

[Barry]

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.
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

 

[Herb Martin]

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.

 

[Paulo Faustino]

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.


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?

 

[Herb Martin]

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.)

 

[Barry]

Hmm interesting,
We are a multimedia company and so will always like to keep out public
facing DNS in our own hands. But I can see your point. We'll add fault
tolerence by using our ISP as a secondary (although we didn't do that in the
past our new ISP is much more accommodating and accessible).

I like the idea of decreasing the TTL to something smaller. Thanks for the
thoughts so far.

Cheers
Barry

 

[Herb Martin]

Hmm interesting,
We are a multimedia company and so will always like to keep out public
facing DNS in our own hands. But I can see your point. We'll add fault
tolerence by using our ISP as a secondary (although we didn't do that in
the past our new ISP is much more accommodating and accessible).

I like the idea of decreasing the TTL to something smaller. Thanks for the
thoughts so far.

That (TTL adjustment) is pretty much all you need to (and you do need to)
do.

 

[Paulo Faustino]

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.

 

[Herb Martin]

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>

 

[Paulo Faustino]

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>

Options are options and to each their own.
Judgments have no place when providing/requesting help

 

[Herb Martin]

Options are options and to each their own.
Judgments have no place when providing/requesting help

Including the comment in the paragraph above then.