<chapter id="problems">
<chapterinfo>
&author.jerry;
&author.jelmer;
&author.dbannon;
<pubdate>8 Apr 2003</pubdate>
</chapterinfo>
<title>Analysing and solving samba problems</title>
<para>
There are many sources of information available in the form
of mailing lists, RFC's and documentation. The docs that come
with the samba distribution contain very good explanations of
general SMB topics such as browsing.</para>
<sect1>
<title>Diagnostics tools</title>
<para>With SMB networking, it is often not immediately clear what
the cause is of a certain problem. Samba itself provides rather
useful information, but in some cases you might have to fall back
to using a <emphasis>sniffer</emphasis>. A sniffer is a program that
listens on your LAN, analyses the data sent on it and displays it
on the screen.</para>
<sect2>
<title>Debugging with Samba itself</title>
<para>
One of the best diagnostic tools for debugging problems is Samba itself.
You can use the <option>-d option</option> for both &smbd; and &nmbd; to specify what
<smbconfoption><name>debug level</name></smbconfoption> at which to run. See the man pages on smbd, nmbd and
smb.conf for more information on debugging options. The debug
level can range from 1 (the default) to 10 (100 for debugging passwords).
</para>
<para>
Another helpful method of debugging is to compile samba using the
<userinput>gcc -g </userinput> flag. This will include debug
information in the binaries and allow you to attach gdb to the
running smbd / nmbd process. In order to attach gdb to an smbd
process for an NT workstation, first get the workstation to make the
connection. Pressing ctrl-alt-delete and going down to the domain box
is sufficient (at least, on the first time you join the domain) to
generate a 'LsaEnumTrustedDomains'. Thereafter, the workstation
maintains an open connection, and therefore there will be an smbd
process running (assuming that you haven't set a really short smbd
idle timeout) So, in between pressing ctrl alt delete, and actually
typing in your password, you can attach gdb and continue.
</para>
<para>
Some useful samba commands worth investigating:
</para>
<screen>
&prompt;<userinput>testparm | more</userinput>
&prompt;<userinput>smbclient -L //{netbios name of server}</userinput>
</screen>
</sect2>
<sect2>
<title>Tcpdump</title>
<para><ulink url="http://www.tcpdump.org/">Tcpdump</ulink> was the first
unix sniffer with SMB support. It is a command-line utility and
nowadays, it's SMB support is somewhat less then that of ethereal
and tethereal.</para>
</sect2>
<sect2>
<title>Ethereal</title>
<para>
<ulink url="http://www.ethereal.com/">Ethereal</ulink> is a graphical
sniffer, available for both unix (Gtk) and Windows. Ethereal's
SMB support is very good.</para>
<para>For details on the use of ethereal, read the well-written
ethereal User Guide.</para>
<para>
Listen for data on ports 137, 138, 139 and 445. E.g.
use the filter <userinput>port 137 or port 138 or port 139 or port 445</userinput>.</para>
<para>A console version of ethereal is available as well and is called
<command>tethereal</command>.</para>
</sect2>
<sect2>
<title>The Windows Network Monitor</title>
<para>
For tracing things on the Microsoft Windows NT, Network Monitor
(aka. netmon) is available on the Microsoft Developer Network CD's,
the Windows NT Server install CD and the SMS CD's. The version of
netmon that ships with SMS allows for dumping packets between any two
computers (i.e. placing the network interface in promiscuous mode).
The version on the NT Server install CD will only allow monitoring
of network traffic directed to the local NT box and broadcasts on the
local subnet. Be aware that Ethereal can read and write netmon
formatted files.
</para>
<sect3>
<title>Installing 'Network Monitor' on an NT Workstation</title>
<para>
Installing netmon on an NT workstation requires a couple
of steps. The following are for installing Netmon V4.00.349, which comes
with Microsoft Windows NT Server 4.0, on Microsoft Windows NT
Workstation 4.0. The process should be similar for other versions of
Windows NT / Netmon. You will need both the Microsoft Windows
NT Server 4.0 Install CD and the Workstation 4.0 Install CD.
</para>
<para>
Initially you will need to install <application>Network Monitor Tools and Agent</application>
on the NT Server. To do this
</para>
<itemizedlist>
<listitem><para>Goto <guibutton>Start</guibutton> - <guibutton>Settings</guibutton> - <guibutton>Control Panel</guibutton> -
<guibutton>Network</guibutton> - <guibutton>Services</guibutton> - <guibutton>Add</guibutton> </para></listitem>
<listitem><para>Select the <guilabel>Network Monitor Tools and Agent</guilabel> and
click on <guibutton>OK</guibutton>.</para></listitem>
<listitem><para>Click <guibutton>OK</guibutton> on the Network Control Panel.
</para></listitem>
<listitem><para>Insert the Windows NT Server 4.0 install CD
when prompted.</para></listitem>
</itemizedlist>
<para>
At this point the Netmon files should exist in
<filename>%SYSTEMROOT%\System32\netmon\*.*</filename>.
Two subdirectories exist as well, <filename>parsers\</filename>
which contains the necessary DLL's for parsing the netmon packet
dump, and <filename>captures\</filename>.
</para>
<para>
In order to install the Netmon tools on an NT Workstation, you will
first need to install the 'Network Monitor Agent' from the Workstation
install CD.
</para>
<itemizedlist>
<listitem><para>Goto <guibutton>Start</guibutton> - <guibutton>Settings</guibutton> - <guibutton>Control Panel</guibutton> -
<guibutton>Network</guibutton> - <guibutton>Services</guibutton> - <guibutton>Add</guibutton></para></listitem>
<listitem><para>Select the <guilabel>Network Monitor Agent</guilabel> and click
on <guibutton>OK</guibutton>.</para></listitem>
<listitem><para>Click <guibutton>OK</guibutton> on the Network Control Panel.
</para></listitem>
<listitem><para>Insert the Windows NT Workstation 4.0 install
CD when prompted.</para></listitem>
</itemizedlist>
<para>
Now copy the files from the NT Server in <filename>%SYSTEMROOT%\System32\netmon\*.*</filename>
to <filename>%SYSTEMROOT%\System32\netmon\*.*</filename> on the Workstation and set
permissions as you deem appropriate for your site. You will need
administrative rights on the NT box to run netmon.
</para>
</sect3>
<sect3>
<title>Installing 'Network Monitor' on an 9x Workstation</title>
<para>
To install Netmon on a Windows 9x box install the network monitor agent
from the Windows 9x CD (<filename>\admin\nettools\netmon</filename>). There is a readme
file located with the netmon driver files on the CD if you need
information on how to do this. Copy the files from a working
Netmon installation.
</para>
</sect3>
</sect2>
</sect1>
<sect1>
<title>Useful URLs</title>
<itemizedlist>
<listitem><para>See how Scott Merrill simulates a BDC behavior at
<ulink noescape="1" url="http://www.skippy.net/linux/smb-howto.html">
http://www.skippy.net/linux/smb-howto.html</ulink>. </para></listitem>
<listitem><para>FTP site for older SMB specs:
<ulink noescape="1" url="ftp://ftp.microsoft.com/developr/drg/CIFS/">
ftp://ftp.microsoft.com/developr/drg/CIFS/</ulink></para></listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Getting help from the mailing lists</title>
<para>
There are a number of Samba related mailing lists. Go to <ulink
noescape="1" url="http://samba.org">http://samba.org</ulink>, click on your nearest mirror
and then click on <command>Support</command> and then click on <command>
Samba related mailing lists</command>.
</para>
<para>
For questions relating to Samba TNG go to
<ulink noescape="1" url="http://www.samba-tng.org/">http://www.samba-tng.org/</ulink>
It has been requested that you don't post questions about Samba-TNG to the
main stream Samba lists.</para>
<para>
If you post a message to one of the lists please observe the following guide lines :
</para>
<itemizedlist>
<listitem><para>Always remember that the developers are volunteers, they are
not paid and they never guarantee to produce a particular feature at
a particular time. Any time lines are 'best guess' and nothing more.
</para></listitem>
<listitem><para>Always mention what version of samba you are using and what
operating system its running under. You should probably list the
relevant sections of your &smb.conf; file, at least the options
in [global] that affect PDC support.</para></listitem>
<listitem><para>In addition to the version, if you obtained Samba via
CVS mention the date when you last checked it out.</para></listitem>
<listitem><para> Try and make your question clear and brief, lots of long,
convoluted questions get deleted before they are completely read !
Don't post html encoded messages (if you can select colour or font
size its html).</para></listitem>
<listitem><para> If you run one of those nifty 'I'm on holidays' things when
you are away, make sure its configured to not answer mailing lists.
</para></listitem>
<listitem><para> Don't cross post. Work out which is the best list to post to
and see what happens, i.e. don't post to both samba-ntdom and samba-technical.
Many people active on the lists subscribe to more
than one list and get annoyed to see the same message two or more times.
Often someone will see a message and thinking it would be better dealt
with on another, will forward it on for you.</para></listitem>
<listitem><para>You might include <emphasis>partial</emphasis>
log files written at a debug level set to as much as 20.
Please don't send the entire log but enough to give the context of the
error messages.</para></listitem>
<listitem><para>(Possibly) If you have a complete netmon trace ( from the opening of
the pipe to the error ) you can send the *.CAP file as well.</para></listitem>
<listitem><para>Please think carefully before attaching a document to an email.
Consider pasting the relevant parts into the body of the message. The samba
mailing lists go to a huge number of people, do they all need a copy of your
smb.conf in their attach directory?</para></listitem>
</itemizedlist>
</sect1>
<sect1>
<title>How to get off the mailing lists</title>
<para>To have your name removed from a samba mailing list, go to the
same place you went to to get on it. Go to <ulink
noescape="1" url="http://lists.samba.org/">http://lists.samba.org</ulink>,
click on your nearest mirror and then click on <command>Support</command> and
then click on <command> Samba related mailing lists</command>.
</para>
<para>
Please don't post messages to the list asking to be removed, you will just
be referred to the above address (unless that process failed in some way...)
</para>
</sect1>
</chapter>