DNS confusion (mine!)

Mark_Andrews at isc.org Mark_Andrews at isc.org
Tue Jul 29 00:12:29 UTC 2003


> This issue is driving me and a few users nuts & I was hoping somebody could
> help me out. I'm having a few problems with DNS for float.com.au and
> ipo-australia.com
> 
> On Monday 21 July I moved float.com.au and ipo-australia.com  to a server at
> linode.com . I also started using using www.zoneedit.com for DNS. The DNS
> should have resolved by now but some ISPs seem to be resolving to the old
> address.
> 
> The new IP address I was given by linode.com works http://64.5.53.79/
> 
> A traceroute of float.com.au from the University of Queensland
> http://www.questnet.net.au/cgi-bin/nph-tr1.cgi   seems to be working:
> traceroute to float.com.au (64.5.53.79) from 130.102.5.50, 30 hops max, 40
> byte packets
>  1  mr2fw-a5 (130.102.5.30)  1.553 ms (ttl=64)  1.068 ms (ttl=64)  1.097 ms
> (ttl=64)
> ... (intermediate steps deleted)
> 20  li-79.members.linode.com (64.5.53.79)  214.269 ms (ttl=45)  215.121 ms
> (ttl=45)  214.742 ms (ttl=45)
> 
> 
> But a traceroute from Telstra
> http://tcruskit.telstra.net/cgi-bin/trace?float.com.au  resolves to the old
> address:
>  traceroute to float.com.au (64.247.30.103), 30 hops max, 40 byte packets
>  1  FastEthernet6-0.civ-service1.Canberra.telstra.net (203.50.1.65)  0.391
> ms  0.436 ms  0.429 ms
> ... (intermediate steps deleted)
> 15  64.247.30.103 (64.247.30.103)  292.62 ms  292.844 ms  293.351 ms
> 
> I'm no DNS expoert so could somebody point out what could be wrong?
> Thanks,
> G. Toomey

	Ensure that the *old* nameservers have the *new* zone content
	or that the old servers are no longer serving the zone.
	The best strategy is to make them serve the new content
	until all NS records refering to them have expired then to
	remove the zone.

	You can get "server lock" if you don't do this.

	"Server lock" is where the cache re-learns the old NS RRset
	every time it makes a query to the old servers resetting
	the TTL.   If it continues to make queries before the NS
	RRset expires it will never go to the parent zone.

	Making the old servers serve the new content forces the
	cache to learn the new RRset.  Just decommisioning the old
	servers make the zone lame for that cache until the NS RRset
	expires.

	Mark
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org


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