[Samba] webDAV (webclient) interferes with XP logons

[David Mathog]

Very long story short...

1.  Samba server on machine running iptables or behind a firewall
2.  Client XP domain logins taking 45 seconds or more.
3.  The problem: webDAV (webclient) is running on the XP workstations
     and this mysteriously triggers access to port 80 on the file server,
     which in turn adds up to long delays.

If you are running an HTTP server and it isn't blocked then these
accesses are rejected and they cause little delay.

If you aren't running a firewall then they are again rejected, and 
again, no delay.

However, if you have a well configured firewall, and you're
not running a web server, then these packets are dropped.  This
causes the XP client to wait for the connections to timeout which
takes FOREVER. This also apparently causes the
"slow file open dialog" problem.  This is where a "file -> open"
dialog takes at least 10 to 20 seconds to show files.

Solutions:

1.  Configure iptables to REJECT (not DROP) connections to the Samba
server's port 80.

OR

2.  Disable webclient on each workstation.  (control panel -> 
administrator tools -> services -> webclient (set STOP and DISABLE).

The first one drops login times down into the 17-20 second range.  The
second one does the same thing and tends to be more in the lower end
of that range (I have not done extensive timing.)  However, it 
presumably will eventually break something that actually needs webDAV.

This is information gleaned from a couple of hours googling and then 
jiggling smb.conf and XP settings.

Personally I think this is a massive bug in XP. There's absolutely no 
reason why SMB connections should trigger web accesses back to the
file server.

Samba 3.0.6 (probably irrelevant)
Mandrake 10.0 (probably irrelevant)
iptables running (relevant)
XP PRO SP1 fully patched except for SP2 as of 9/24/04 (most relevant)

Regards,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech