Local domain tries Internet resolution????

[Mark_Andrews at isc.org]

> 
> My nameserver (BIND v9.2.0, on a Linux box) provides local name 
> resolution and caching of Internet resolutions.  I've noticed that when 
> my Internet connection is down, resolution by local machine name only takes 
> a long time.  Why is this?

	Because the client walked the search list looking for AAAA
	address then tried the name "as is" which requires talking
	to the root servers.
 
> With a Net connection up, resolution of local machines names is 
> apparently instantaneous.  With no Net connection, resolution of local 
> address take ~30 seconds before suceeding. 
> 
> Resolution of the local name + domain ("earth.snydernet.lan") is always 
> fast where resolutions of just the name ("earth") experience a timeout on 
> the absence of Internet access.  This suggests to me that BIND is trying 
> to contact nameservers outside my LAN to resolve short names.
> 
> I don't get this at all.  Shouldn't BIND try to resolve simple names 
> locally and only go to the root/TLD nameservers of no local match is 
> found?
> 
> Here's an example of the problem, a resolution of machine "mercury" on my 
> network.  This is a single resolution taken from the BIND query log file:
> 
> 10:38:06.000 queries: client 127.0.0.1#32797: query: mercury.snydernet.lan 
> IN AAAA
> 10:38:06.006 queries: client 127.0.0.1#32797: query: mercury IN AAAA
> 10:38:20.040 queries: client 127.0.0.1#32797: query: mercury IN AAAA
> 10:38:34.073 queries: client 127.0.0.1#32799: query: mercury.snydernet.lan 
> IN A
> 
> Note that the resolution took over 28 seconds to accomplish.
> 
> I'm attaching my "named.conf" and what I hope is the relevant zone file 
> below.  Can anyone tell me why BIND wants Internet access for resolving 
> simple names?
> 
> Thank you.
> 
> --- file "named.conf" -------------------------------------
> 
> options {
>    directory "/var/named/snydernet";
> 
>    listen-on { 127.0.0.1; 192.168.0.1; };
>    allow-query { 127.0.0.1; 192.168.0/24; };
> 
>    auth-nxdomain no;
>    transfer-format many-answers;
> 
>    cleaning-interval 120;
>    interface-interval 0;
> };
> 
> controls {
>    inet 127.0.0.1 allow { localhost; }  keys { rndckey; };
> };
> 
> zone "." {
>    type hint;
>    file "db.cache";
> };
> 
> zone "snydernet.lan" {
>    type master;
>    file "db.snydernet";
> };
> 
> zone "0.0.127.IN-ADDR.ARPA" {
>    type master;
>    file "db.127.0.0";
>    notify no;
> };
> 
> zone "0.168.192.IN-ADDR.ARPA" {
>    type master;
>    file "db.192.168.0";
> };
> 
> include "/etc/rndc.key";
> 
> 
> --- file "db.snydernet" -------------------------------------
> 
> 
> $INCLUDE snydernet.soa
> 
> ; computers
> localhost               IN      A       127.0.0.1
> sunburn                 IN      A       192.168.0.1
> mercury                 IN      A       192.168.0.2
> venus                   IN      A       192.168.0.3
> earth                   IN      A       192.168.0.4
> mars                    IN      A       192.168.0.5
> jupiter                 IN      A       192.168.0.6
> saturn                  IN      A       192.168.0.7
> uranus                  IN      A       192.168.0.8
> neptune                 IN      A       192.168.0.9
> pluto                   IN      A       192.168.0.10
> 
> ; printers
> dj1120                  IN      A       192.168.0.17
> lj4500                  IN      A       192.168.0.18
> 
> ; mail exchangers
> snydernet.lan.          IN      MX 10   sunburn.snydernet.lan.
> 
> ; aliases
> ftp.snydernet.lan.      IN      CNAME   sunburn.snydernet.lan.
> www.snydernet.lan.      IN      CNAME   sunburn.snydernet.lan.
> q3a.snydernet.lan.      IN      CNAME   sunburn.snydernet.lan.
> proxy.snydernet.lan.    IN      CNAME   sunburn.snydernet.lan.
> print.snydernet.lan.    IN      CNAME   sunburn.snydernet.lan.
> time.snydernet.lan.     IN      CNAME   sunburn.snydernet.lan.
> 
> --- end of attched files -----------------------------
> 
> 
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org