[olug] Domain name propagation - how long?

Thom id4spam at cox.net
Wed Oct 29 23:27:48 UTC 2003


Thanks everyone, DNS has never been my strong point.
Guess I better study up on it!

Thom

Brian Wiese wrote:

>On Wed, 29 Oct 2003 14:59:35 -0600
>Thom <id4spam at cox.net> wrote:
>
>|I ran some tests:
>|
>|# host thom.homelinux.com
>|Host thom.homelinux.com not found: 3(NXDOMAIN)
>...
>|Where's the delay?
>
>You are not updating a "2nd level domain name" (i.e. domain.com) with the
>root servers where they are responsible for the *.tld domains, but rather
>you are dynamically updating a "3rd level domain name" (i.e.
>3rdlvl.domain.com) where the authority for that dns->IP address mapping
>usually resides with the "homelinux.com" DNS server, but actually the
>dyndns.org servers in this case since it seems like homelinux.com is
>something they run[1].  
>
>By running your dyndns update, you're updating the "authoritative" name
>server for those 3rd level domains (ns1.dyndns.org, etc).  Any new
>requests that have to be resolved will ask that authoritative name server,
>and of course hopefully get the right response since you just told them
>what your new IP addy is.
>
>I'm actually suprised that it updated the new IP address almost
>"instantly".  Usually the name server you use (cox's nameservers) which
>sends the request along to the ns*.dyndns.com nameservers, would keep that
>resolution information in cache for a couple minutes -- incase anyone else
>on the cox network wanted to know who "thom.homelinux.com" was (and its
>most unlikely those shouldn't change within minutes/hours/days in most
>cases).  So I would have expected for you to get your old IP back from a
>resolution, for at least the next couple of minutes-- or perhaps cox NSs
>are not caching.
>
>A 2nd level domain then (.net, .com, .org, etc.. are the top level
>domains, TLD), like dyndns.org, when its setup needs an authoritative NS
>(the root servers responsible for the .org TLD) to tell people how to get
>there.  So, you ask the root dns servers for *.tld, and you ask the
>dyndns.org servers for *.dnydns.org.  Its a heirarchy. 
>
>[1] 
>bwiese at franklin:~$ dig thom.homelinux.com
><snip>
>;; ANSWER SECTION:
>thom.homelinux.com.     60      IN      A       68.13.170.107
>
>;; AUTHORITY SECTION:
>homelinux.com.          86400   IN      NS      ns5.dyndns.org.
>homelinux.com.          86400   IN      NS      ns1.dyndns.org.
>homelinux.com.          86400   IN      NS      ns2.dyndns.org.
>homelinux.com.          86400   IN      NS      ns3.dyndns.org.
>homelinux.com.          86400   IN      NS      ns4.dyndns.org.
>
>
> Brian Wiese | bwiese(at)cotse.com | aim: unolinuxguru
>-------------------------------------------------------
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