All name servers on one segment?

[James Raftery]

On Mon, May 07, 2001 at 06:25:54PM +0100, Simon Waters wrote:
> okay sequential IP addresses look bad, but it is
> possible for adjacent TCP/IP addresses to offer a fair
> degree of redundancy (Okay it is very unlikely, but it is
> possible *8-).

With properly implemented anycast adjacent (or identical) IP numbers can
be highly redundant.

> Traceroute will tell us if they are located behind the same
> router from us, but as pointed out the router may not be a
> single point of failure.

All traceroute will show you is the routing system's "best path" at a
given moment in time. If that path fails, the next best path will
(should) carry the packets instead.

> Most of the big ISP's I've looked at have one DNS server
> that is clearly located "somewhere else".

This is a good idea. To counter a mega routing snafu, servers in
seperate AS's makes sense.

> Alas, the best I can offer is checking the web site, or
> guessing at the meaning of the cryptic router names from
> traceroute, for determining geographical redundancy.

Ask your provider. Ask detailed, nasty questions. They may not answer,
but remind them that you may not give them your business.


james
-- 
James Raftery (JBR54)
  "It's somewhere in the Red Hat district"  --  A network engineer's
   freudian slip when talking about Amsterdam's nightlife at RIPE 38.