chicken and egg question

[Cricket Liu]

> anyhow.  a domain i'm admining (hpapts.com) has its ns provided by
> qwest (who provides our T1).  i'm wanting to take control of our own
> DNS.
>
> so, i'm registered with netsol.  on their make changes page they
> insist that i provide a FQDN for the name servers.
>
> my name servers will be named ns1.hpapts.com and ns2.hpapts.com.
>
> ... but how will netsol know what IP addys those names refer to?

You have to specify the IP addresses during the registation
process.

> here's (perhaps) a more meatier question:
>
> with MX records it's possible to define secondary, tertiary, etc mail
> addresses to attempt to deliver to.  is it possible to do something
> similar for our web server?

Not really.  There's a relatively new record type, the SRV record,
that lets you do that, but I don't know of any web browsers that
actually look up and use SRV records.

> i've got my mail server dual homed on two different T1 lines; if the
> primary T1 goes down, users are able to access the second T1 fairly
> seamlessly (i think).
>
> is there a way to do the same with our web server?  right now i'm
> hatching an insane scheme that involves two name servers, one on each
> T1, each with different IP records for hpapts.com.  in theory, if the
> primary T1 goes down, those attempting to access the site will hit the
> secondary NS on the *other* T1 and get the other IP ...
>
> or am i just smoking something?

That's actually a very good idea.  During normal operation, when both
T1s are up, many remote name servers will "lock on" to the hpapts.com
name server closest to them, and will therefore send traffic to the web
server across the T1 that leads to that name server.

The trouble, really, is caching.  If the TTL on your web server's address
is too long, then someone who's just accessed your web server across
one T1 will keep doing so until the address record times out.  If that T1
fails during that period, there's no automatic failover to the other.  So
I'd
suggest keeping that TTL short.

cricket

Men & Mice
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