All nameservers unresponsive when master is down

[Mark_Andrews at isc.org]

> My domain `hpdsc.com` has 2 "actual" nameservers which we present to the
> world as 4 "logical" nameservers. The 2 boxes are multihomed and all 4
> addresses are given as valid namesevers for the domain (we have 2 leased
> lines and this removes a single point of failure).
> 
> My whois informations is:
> 
>  Domain servers in listed order:
> 
>    NS2.HPDSC.COM                212.158.99.195
>    NS3.HPDSC.COM                195.167.246.3
>    NS4.HPDSC.COM                195.167.246.4
>    NS1.HPDSC.COM                212.158.99.194	The like-typed nameserv
> ers
> are actually the same nameserver on the same box (multihomed).

	Unless you are playing with /32's you are still subject to single
	points of failure.

> 
> The relevant part of the Zone data is:
> 
> hpdsc.com.      IN      SOA     ns1.hpdsc.com. dnsadmin.hpdsoftware.com. (
>                                         1018281163      ; Serial
>                                         7200            ; refresh (2 hour)
>                                         3600            ; retry (1 hours)
>                                         604800          ; expire (1 week)
>                                         1               ; neg. cache
>                                         )
> ...
> hpdsc.com.      NS      ns1.hpdsc.com.
> hpdsc.com.      NS      ns2.hpdsc.com.
> hpdsc.com.      NS      ns3.hpdsc.com.
> hpdsc.com.      NS      ns4.hpdsc.com.
> ...
> 
> ns1.hpdsc.com.          IN A            212.158.99.194
> ns2.hpdsc.com.          IN A            212.158.99.195
> ns3.hpdsc.com.          IN A            195.167.246.3
> ns4.hpdsc.com.          IN A            195.167.246.4

	Well before you do anything else supply reasonable TTL values.
	1 second (above) isn't reasonable nor is zero which the server
	currently emitting.

> However, if I stop BIND running on ns1 (which is also ns3 if referenced by
> it's alternative IP address) then the whole Zone stops resolving. And I
> can't for the life of me work out why. If you want to tell me to "FAQ off"
> then please do.

	Well the zone resolves fine except for some delays cause by the
	zero TTLs you are currently using.

> 
> Any help/pointers/soothing words of calm would be most appreciated: I'm
> terrified on ns1/ns3 falling over! I'm running BIND9.
> _________________________________________
> 
> 
> Sam Pointer - HPD Software Ltd.
> Email:   sam.pointer at hpdsoftware.com
> 
> Sites:      http://slashdot.org   http://www.perl.com  http://eff.org
>                   http://www.gnu.org/software/hurd/hurd.html 
> 
> 
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--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org