[TriLUG] Slides from last night's DNS Presentation
clubjuggler at gmail.com
Fri Oct 15 14:06:54 EDT 2004
On Fri, 15 Oct 2004 11:28:37 -0400 (EDT), Matt Pusateri
<mpusateri at wickedtrails.com>
> Second, Wouldn't it also be possible for a server to be lame due to a
> valid DNS change that hasn't propagated through to all name servers
> yet. For example, you make a request to your ISP name server since
> you are using it as a forwarder. They have example.com cached so they
> give you the NS from their cache. Unfortunately example.com just made
> a network change either changed ISP's or servers or whatever so the
> information that your ISP had cached is no longer accurate. Hopefully
> example.com wouldn't get rid of their old name server until the new
> one propageted, but I could see how some sites due to resources or
> politics wouldn't have that choice. Or have I missed something here.
Yes, you've missed something. A lame server is a server basically a
server that is listed as being "authoritative" (there's a term that should
probably be defined) for a domain but when queried answers with a
"non-authoritive" answer. See this link for more information:
 An "authoritative" server is what that doesn't have to query another
server in response to a domain query. This includes master server
*and* slave servers (because a slave server doesn't "query" master
server, it transfers entire zones at a time). Authoritative servers should
be all servers referenced in NS records for a domain. For example, for
trilug, you can use the host command to see it's name servers:
% host -t ns trilug.org
trilug.org name server ns.wayfarer.org.
trilug.org name server ns.trilug.org.
But, if you do a "whois trilug.org" you actually get 3 name servers
listed (hmm... perhaps we should fix that!). Anyway, that's what
an "authoritative" server is.
More information about the TriLUG