Domain unresolved in Singapore

Jeff Reasoner jeff.reasoner at mail.hccanet.org
Tue Feb 19 15:02:31 UTC 2008


On Tue, 2008-02-19 at 09:43 +0100, Stephane Bortzmeyer wrote:
> On Tue, Feb 19, 2008 at 03:30:48PM +0700,
>  Kadek Hendra Lesmana <ikadek at gmail.com> wrote 
>  a message of 10 lines which said:
> 
> > Why this address is unresolved in Singapore but it's okay in Germany?
> > I checked with DNS Report from DNS-Stuff and no error, only some
> > warning.
> 
> Bad tools, use another tool.
> 
> Zonecheck (http://www.zonecheck.fr/) clearly indicates the problem:
> only two name servers and probably in the same room, which means that
> any network glitch will prevent name resolution. Use more diverse name servers.

The fact that these servers are on the same subnet or in the same AS
does not necessarily mean they're in the same room. There are plenty of
ways to build fault tolerance into the underlying network that render
this kind of warning meaningless.

Maybe they are in the same room, and there was a problem with one or
both at the time the OP was testing. They certainly are up now.

Is the problem ongoing? What does a dig +trace guentner-asiapacific.com
from Singapore look like?

> w> IP addresses are likely to be all on the same subnet
>  | Adv: ZoneCheck
>  |   To avoid loosing all connectivity with the authoritative DNS in case
>  | of network outage it is advised to host the DNS on different networks.
>  | 
>  | Ref: IETF RFC2182 (Abstract)
>  |   The Domain Name System requires that multiple servers exist for every
>  | delegated domain (zone). This document discusses the selection of
>  | secondary servers for DNS zones. Both the physical and topological
>  | location of each server are material considerations when selecting
>  | secondary servers. The number of servers appropriate for a zone is also
>  | discussed, and some general secondary server maintenance issues
>  | considered.
>  `----- -- -- - -  -
>  :   All the servers are likely to be on the subnet 222.124.211.224/28,
>  : try moving some of them to another subnet.
>  `..... .. .. . .  .
> => generic
> 
> w> Nameservers are all part of the same AS
>  | Adv: ZoneCheck
>  |   To avoid loosing all connectivity with the authoritative DNS in case
>  | of a routing problem inside your Autonomous System, it is advised to
>  | host the DNS on different AS.
>  `----- -- -- - -  -
>  :   All the nameservers are part of the same Autonomous System (AS number
>  : 17974), try to have some of them hosted on another AS.
>  `..... .. .. . .  .
> => generic
> 
-- 
Jeff Reasoner
HCCA
513 728-7902 voice



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