forwarders without a forwarders directive
Dave Sparro
dsparro at gmail.com
Tue Jan 31 13:55:15 UTC 2006
On 29 Jan 2006 08:30:13 -0800, rsesnaski at yahoo.com <rsesnaski at yahoo.com> wrote:
> I took over administration at a new company and for the life of me
> I can't see how their external addresses (www.google.com) resolv
> without a named.conf fowarders directive. Is there something I missing
> or some sort of fall back position to a default gateway?
DNS forwarders should be the exception, not the rule. The best way
for a caching DNS server to get it's information from the Internet is
through a series of iterative queries following the chain of
delegation from the root to the authoritative servers for the domain
in question. For example :
; <<>> DiG 9.2.2 <<>> +trac www.google.com
;; global options: printcmd
. 227864 IN NS I.ROOT-SERVERS.NET.
. 227864 IN NS J.ROOT-SERVERS.NET.
. 227864 IN NS K.ROOT-SERVERS.NET.
. 227864 IN NS L.ROOT-SERVERS.NET.
. 227864 IN NS M.ROOT-SERVERS.NET.
. 227864 IN NS A.ROOT-SERVERS.NET.
. 227864 IN NS B.ROOT-SERVERS.NET.
. 227864 IN NS C.ROOT-SERVERS.NET.
. 227864 IN NS D.ROOT-SERVERS.NET.
. 227864 IN NS E.ROOT-SERVERS.NET.
. 227864 IN NS F.ROOT-SERVERS.NET.
. 227864 IN NS G.ROOT-SERVERS.NET.
. 227864 IN NS H.ROOT-SERVERS.NET.
;; Received 276 bytes from 192.168.1.20#53(192.168.1.20) in 5 ms
com. 172800 IN NS K.GTLD-SERVERS.NET.
com. 172800 IN NS L.GTLD-SERVERS.NET.
com. 172800 IN NS M.GTLD-SERVERS.NET.
com. 172800 IN NS A.GTLD-SERVERS.NET.
com. 172800 IN NS B.GTLD-SERVERS.NET.
com. 172800 IN NS C.GTLD-SERVERS.NET.
com. 172800 IN NS D.GTLD-SERVERS.NET.
com. 172800 IN NS E.GTLD-SERVERS.NET.
com. 172800 IN NS F.GTLD-SERVERS.NET.
com. 172800 IN NS G.GTLD-SERVERS.NET.
com. 172800 IN NS H.GTLD-SERVERS.NET.
com. 172800 IN NS I.GTLD-SERVERS.NET.
com. 172800 IN NS J.GTLD-SERVERS.NET.
;; Received 504 bytes from 192.36.148.17#53(I.ROOT-SERVERS.NET) in 7 ms
google.com. 172800 IN NS ns1.google.com.
google.com. 172800 IN NS ns2.google.com.
google.com. 172800 IN NS ns3.google.com.
google.com. 172800 IN NS ns4.google.com.
;; Received 168 bytes from 192.52.178.30#53(K.GTLD-SERVERS.NET) in 123 ms
www.google.com. 900 IN CNAME www.l.google.com.
l.google.com. 86400 IN NS a.l.google.com.
l.google.com. 86400 IN NS b.l.google.com.
l.google.com. 86400 IN NS c.l.google.com.
l.google.com. 86400 IN NS d.l.google.com.
l.google.com. 86400 IN NS e.l.google.com.
l.google.com. 86400 IN NS g.l.google.com.
;; Received 244 bytes from 216.239.32.10#53(ns1.google.com) in 84 ms
--
Dave
http://dns.thesparros.com/
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