DESKTOP.INI amd & DNS puzzle

[Schell, Robert]

This situation can cause problems on Solaris 2.6 and higher also. If / is 
shared out by Samba and a client opens /home, all home directories 
will be automounted because Explorer looks for desktop.ini in each of
the home directories. In our case that's 5400 mounts. Has anybody 
else run into this situation and come up with a way to avoid all the mounts?

Bob Schell

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David A. De Graaf wrote:

I have long been puzzled at the DNS lookups that occur whenever a
local client tries to view a share on a local server.  My local
network is connected to the world via a modem connection controlled by
diald, so whenever my own DNS can't find a name, BAM!  The dialing
begins.  This is annoying.
I had added the entry in smb.conf:
	name resolve order = wins lmhosts
in a (vain) attempt to suppress DNS lookups by samba, but still they
happened.

I finally tracked the cause.  It's a weird interaction between samba
and amd, the auto-mount daemon.
(The samba-2.0.4b server is on Linux Red Hat 6.0; the client is W98.)

Whenever a client tries to view a share, the server goes through quite
a dance.  With  'debug level = 4'  I can see in the log.client file
many attempts to find and open  'DESKTOP.INI".  Samba looks in several
places for this non-existent file before giving up:

	/DESKTOP.INI
	/DESKTOP.INI
	/DESKTOP.INI
	/DESKTOP.INI
	/PROC/DESKTOP.INI
	/PROC/DESKTOP.INI
	/NET/DESKTOP.INI
	/NET/DESKTOP.INI

It is the last two tries that provoke diald, because  amd  interprets
this as an attempt to auto-mount machine "DESKTOP.INI" at /net.
Since it doesn't know of any such machine, it sends out a DNS request
to resolve this name.  It fails, of course, but not until the official
DNS server gives up.  After a LOOOONG delay, the originally requested
share is opened and displayed to the client.

Curiously, samba looks for /NET/DESKTOP.INI only when the the share is
the root directory of the server.  When a lesser share is viewed the 
/NET prefix isn't used.

I tried to find a workaround, but the amd man page is, shall we say,
opaque.  In /etc/sysconfig/amd I found  /net  specified as the place to
hang all the automounted file systems, so I changed it to /n.
Surprise!   Now samba prepends  /N to DESKTOP.INI and we retain the
problem.

In /etc/amd.conf reside the rules by which amd operates.  There are
only two lines:

    /defaults fs:=${autodir}/${rhost}/root/${rfs};opts:=nosuid,nodev
    *       rhost:=${key};type:=host;rfs:=/

I was unable to comprehend this with the "help" of the man page.
I guessed the '*' was culpable and replaced this line with one
each for my small collection of machines, naming them explicitly
instead of the *.

That did the trick.  Each attempt to open /NET/DESKTOP.INI fails
immediately and the requested share is displayed without delay and
without calling the Internet.

I suppose only God and Mr. Bill know for sure why DESKTOP.INI is
needed, and why samba looks in such unlikely places for it.
I'll pray for an answer, because Mr. Bill surely won't tell.

But maybe some wise mortal out there knows, and will tell us.
I wish I didn't have to enumerate to  amd  the machines to allow,
just because samba looks in funny places for this file.

-- 
	David A. De Graaf    DATIX, Inc.    Hilton Head Is., SC  
	degraaf at rhsnet.com       843-785-3136, -3156 (fax)

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When Samba