Reader Reports 

NS Look Up

To clear up your confusion on the problems with 'nslookup', note that bind's 
resolver library in Mac OS X uses 'lookupd' to resolve names (the library 
sends requests to lookupd; lookupd uses various resources, depending on 
configuration, including DNS and netinfo).

Thus the need for '/etc/resolv.conf' is minimal on a Mac OS X system.  
However, 'nslookup' does use it.  Instead of using the resolver library, 
'nslookup' crafts its own packets to talk with DNS servers.  It will use 
/etc/resolv.conf for configuration info, if present, but as you observe, you 
can also give it that information on the command line, or interactively.

The right behavior for 'nslookup' on Mac OS X/Darwin is to look in netinfo 
for this information, if it's not present on the file system.

To make matters a bit more interesting, '/etc/resolv.conf' is now, usually, 
a symbolic link to '/var/run/resolv.conf'.  The latter is created, or not, 
depending on PPP and a Darwin component called configd.  If PPP is active, 
the DNS info is written to the latter file; and removed when PPP goes 
inaactive.

Hope this helps bring more confusion to your life :-}

Regards,


Justin
Justin C. Walker, Curmudgeon-At-Large   *
Institute for General Semantics         |
Manager, CoreOS Networking              |   Men are from Earth.
Apple Computer, Inc.                    |   Women are from Earth.
2 Infinite Loop                         |       Deal with it.
Cupertino, CA 95014                     |
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