Re: [ILUG] [OT at this stage] Disadvantages of CNAMEs

From: Thomas Bridge (tbridge at domain vianetworks.ie)
Date: Thu 11 Apr 2002 - 16:02:18 IST


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At 15:44 11/04/2002 +0100, Nick Murtagh wrote:

>On Thursday 11 April 2002 15:37, Thomas Bridge wrote:

> > Why redesign to avoid a problem that can be avoided anyway with proper
> > planning?

>So there's never a situation where you have to change DNS records
>unexpectedly without prior knowledge?

Its been a while I have to admit. And the solution was simple. Reduce
the TTL for the relevant records permanently.

If your mail server being out is an issue, reduce the TTL on the A
record. Therefore, if you need to renumber, you're sorted.

>I suppose if you care that much about DNS related outages you would make sure
>that could never happen, eg by duplicating your servers on separate sites,
>using different providers, etc

Or just spend some money on a pair of Layer 4 switches and configure HSRP.

> > Designing protocols to protect the clueless from themselves is not a good
> > idea.
>
>Why?

This essentially boils down to the Mac V Linux argument (at least the old
style Mac, what I'm about to say doesn't apply to OS X).

MacOS hid the dirty, disgusting details of how computers worked from
you. To use a Mac, you didn't need to know anything about how computers
work. To use Linux, required you to have a good understanding of the
internals of computers worked, implications of using different library
sets, etc. etc. But when you tried to burrow down, Linux was far more
flexible as a platform than Mac, and gave you far more freedom to do things
in how you wanted.

Networks should not be designed and run by people who don't know what they
are doing - the requirement that network administrators should actually
understand how the network works is not an unreasonable one, despite the
fact that Microsoft MCSEs don't seem to have grasped this concept yet.

T.

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