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2 <!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
3 <chapter id="problems">
10 <pubdate>8 Apr 2003</pubdate>
13 <title>Analyzing and Solving Samba Problems</title>
16 <indexterm><primary>RFCs</primary></indexterm>
17 <indexterm><primary>SMB</primary></indexterm>
18 <indexterm><primary>documentation</primary></indexterm>
19 There are many sources of information available in the form of mailing lists, RFCs, and documentation. The
20 documentation that comes with the Samba distribution contains good explanations of general SMB topics such as
25 <title>Diagnostics Tools</title>
28 <indexterm><primary>sniffer</primary></indexterm>
29 <indexterm><primary>LAN</primary></indexterm>
30 <indexterm><primary>analyzes data</primary></indexterm>
31 <indexterm><primary>SMB networking</primary></indexterm>
32 <indexterm><primary>network analyzer</primary></indexterm>
33 With SMB networking, it is often not immediately clear what the cause is of a certain problem. Samba itself
34 provides rather useful information, but in some cases you might have to fall back to using a
35 <emphasis>sniffer</emphasis>. A sniffer is a program that listens on your LAN, analyzes the data sent on it,
36 and displays it on the screen.
40 <title>Debugging with Samba Itself</title>
43 <indexterm><primary>diagnostic tools</primary></indexterm>
44 <indexterm><primary>debugging problems</primary></indexterm>
45 <indexterm><primary>smbd</primary></indexterm>
46 <indexterm><primary>nmbd</primary></indexterm>
47 <indexterm><primary>debugging passwords</primary></indexterm>
48 <indexterm><primary>debug level</primary></indexterm>
49 <indexterm><primary>log level</primary></indexterm>
50 One of the best diagnostic tools for debugging problems is Samba itself. You can use the <option>-d
51 option</option> for both &smbd; and &nmbd; to specify the <smbconfoption name="debug level"/> at which to run.
52 See the man pages for <command>smbd, nmbd</command>, and &smb.conf; for more information regarding debugging
53 options. The debug level (log level) can range from 1 (the default) to 10 (100 for debugging passwords).
57 <indexterm><primary>debugging</primary></indexterm>
58 <indexterm><primary>gcc</primary></indexterm>
59 <indexterm><primary>gdb</primary></indexterm>
60 <indexterm><primary>smbd</primary></indexterm>
61 <indexterm><primary>nmbd</primary></indexterm>
62 <indexterm><primary>LsaEnumTrustedDomains</primary></indexterm>
63 <indexterm><primary>attach gdb</primary></indexterm>
64 Another helpful method of debugging is to compile Samba using the <command>gcc -g </command> flag. This will
65 include debug information in the binaries and allow you to attach <command>gdb</command> to the running
66 <command>smbd/nmbd</command> process. To attach <command>gdb</command> to an <command>smbd</command> process
67 for an NT workstation, first get the workstation to make the connection. Pressing ctrl-alt-delete and going
68 down to the domain box is sufficient (at least, the first time you join the domain) to generate a
69 <parameter>LsaEnumTrustedDomains</parameter>. Thereafter, the workstation maintains an open connection and
70 there will be an smbd process running (assuming that you haven't set a really short smbd idle timeout). So, in
71 between pressing <command>ctrl-alt-delete</command> and actually typing in your password, you can attach
72 <command>gdb</command> and continue.
76 Some useful Samba commands worth investigating are:
77 <indexterm><primary>testparm</primary></indexterm>
78 <indexterm><primary>smbclient</primary></indexterm>
80 &prompt;<userinput>testparm | more</userinput>
81 &prompt;<userinput>smbclient -L //{netbios name of server}</userinput>
88 <title>Tcpdump</title>
91 <indexterm><primary>tcpdump</primary></indexterm>
92 <indexterm><primary>tethereal</primary></indexterm>
93 <indexterm><primary>ethereal</primary></indexterm>
94 <ulink url="http://www.tcpdump.org/">Tcpdump</ulink> was the first
95 UNIX sniffer with SMB support. It is a command-line utility and
96 now, its SMB support is somewhat lagging that of <command>ethereal</command>
97 and <command>tethereal</command>.
103 <title>Ethereal</title>
106 <indexterm><primary>ethereal</primary></indexterm>
107 <ulink url="http://www.ethereal.com/">Ethereal</ulink> is a graphical sniffer, available for both UNIX (Gtk)
108 and Windows. Ethereal's SMB support is quite good. For details on the use of <command>ethereal</command>, read
109 the well-written Ethereal User Guide.
112 <figure id="ethereal1"><title>Starting a Capture.</title><imagefile>ethereal1</imagefile></figure>
115 <indexterm><primary>ports</primary></indexterm>
116 Listen for data on ports 137, 138, 139, and 445. For example, use the filter <userinput>port 137, port 138,
117 port 139, or port 445</userinput> as seen in <link linkend="ethereal1">Starting a Capture</link> snapshot.
121 A console version of ethereal is available as well and is called <command>tethereal</command>.
124 <figure id="ethereal2"><title>Main Ethereal Data Window.</title><imagefile>ethereal2</imagefile></figure>
129 <title>The Windows Network Monitor</title>
132 <indexterm><primary>Network Monitor</primary></indexterm>
133 <indexterm><primary>Netmon</primary></indexterm>
134 <indexterm><primary>Microsoft Developer Network CDs</primary></indexterm>
135 <indexterm><primary>SMS</primary></indexterm>
136 <indexterm><primary>promiscuous mode</primary></indexterm>
137 <indexterm><primary>ethereal</primary></indexterm>
138 For tracing things on Microsoft Windows NT, Network Monitor (aka Netmon) is available on Microsoft Developer
139 Network CDs, the Windows NT Server install CD, and the SMS CDs. The version of Netmon that ships with SMS
140 allows for dumping packets between any two computers (i.e., placing the network interface in promiscuous
141 mode). The version on the NT Server install CD will only allow monitoring of network traffic directed to the
142 local NT box and broadcasts on the local subnet. Be aware that Ethereal can read and write Netmon formatted
147 <title>Installing Network Monitor on an NT Workstation</title>
150 <indexterm><primary>Netmon.</primary></indexterm>
151 Installing Netmon on an NT workstation requires a couple of steps. The following are instructions for
152 installing Netmon V4.00.349, which comes with Microsoft Windows NT Server 4.0, on Microsoft Windows NT
153 Workstation 4.0. The process should be similar for other versions of Windows NT version of Netmon. You will
154 need both the Microsoft Windows NT Server 4.0 Install CD and the Workstation 4.0 Install CD.
158 <indexterm><primary>Network Monitor Tools and Agent</primary></indexterm>
159 Initially you will need to install <application>Network Monitor Tools and Agent</application>
160 on the NT Server to do this:
164 <listitem><para>Go to <guibutton>Start</guibutton> -> <guibutton>Settings</guibutton> -> <guibutton>Control Panel</guibutton> ->
165 <guibutton>Network</guibutton> -> <guibutton>Services</guibutton> -> <guibutton>Add</guibutton>.</para></listitem>
167 <listitem><para>Select the <guilabel>Network Monitor Tools and Agent</guilabel> and click on <guibutton>OK</guibutton>.</para></listitem>
169 <listitem><para>Click on <guibutton>OK</guibutton> on the Network Control Panel.</para></listitem>
171 <listitem><para>Insert the Windows NT Server 4.0 install CD when prompted.</para></listitem>
175 At this point, the Netmon files should exist in <filename>%SYSTEMROOT%\System32\netmon\*.*</filename>.
176 Two subdirectories exist as well: <filename>parsers\</filename>, which contains the necessary DLLs
177 for parsing the Netmon packet dump, and <filename>captures\</filename>.
181 To install the Netmon tools on an NT Workstation, you will first need to install the
182 Network Monitor Agent from the Workstation install CD.
186 <listitem><para>Go to <guibutton>Start</guibutton> -> <guibutton>Settings</guibutton> ->
187 <guibutton>Control Panel</guibutton> -> <guibutton>Network</guibutton> ->
188 <guibutton>Services</guibutton> -> <guibutton>Add</guibutton>.</para></listitem>
190 <listitem><para>Select the <guilabel>Network Monitor Agent</guilabel>, click on
191 <guibutton>OK</guibutton>.</para></listitem>
193 <listitem><para>Click on <guibutton>OK</guibutton> in the Network Control Panel.
196 <listitem><para>Insert the Windows NT Workstation 4.0 install CD when prompted.</para></listitem>
200 Now copy the files from the NT Server in <filename>%SYSTEMROOT%\System32\netmon</filename>
201 to <filename>%SYSTEMROOT%\System32\netmon</filename> on the workstation and set permissions
202 as you deem appropriate for your site. You will need administrative rights on the NT box to run Netmon.
207 <title>Installing Network Monitor on Windows 9x/Me</title>
209 To install Netmon on Windows 9x/Me, install the Network Monitor Agent
210 from the Windows 9x/Me CD (<filename>\admin\nettools\netmon</filename>).
211 There is a readme file included with the Netmon driver files on the CD if you need
212 information on how to do this. Copy the files from a working Netmon installation.
219 <title>Useful URLs</title>
222 <listitem><para>See how Scott Merrill simulates a BDC behavior at
223 <ulink noescape="1" url="http://www.skippy.net/linux/smb-howto.html">
224 http://www.skippy.net/linux/smb-howto.html</ulink>. </para></listitem>
226 <listitem><para>FTP site for older SMB specs,
227 <ulink noescape="1" url="ftp://ftp.microsoft.com/developr/drg/CIFS/">
228 ftp://ftp.microsoft.com/developr/drg/CIFS/</ulink></para></listitem>.
235 <title>Getting Mailing List Help</title>
238 There are a number of Samba-related mailing lists. Go to <ulink
239 noescape="1" url="http://samba.org">http://samba.org</ulink>, click on your nearest mirror,
240 and then click on <command>Support</command>. Next, click on <command>
241 Samba-related mailing lists</command>.
245 For questions relating to Samba TNG, go to
246 <ulink noescape="1" url="http://www.samba-tng.org/">http://www.samba-tng.org/</ulink>.
247 It has been requested that you do not post questions about Samba-TNG to the
248 mainstream Samba lists.</para>
251 If you do post a message to one of the lists, please observe the following guidelines:
257 <indexterm><primary>volunteers</primary></indexterm>
258 Always remember that the developers are volunteers; they are
259 not paid and they never guarantee to produce a particular feature at
260 a particular time. Any timelines are <quote>best guess,</quote> and nothing more.
264 <indexterm><primary>PDC</primary></indexterm>
265 Always mention what version of Samba you are using and what
266 operating system it's running under. You should list the relevant sections of
267 your &smb.conf; file, at least the options in <smbconfsection name="[global]"/>
268 that affect PDC support.
271 <listitem><para>In addition to the version, if you obtained Samba via
272 CVS, mention the date when you last checked it out.</para></listitem>
274 <listitem><para> Try to make your questions clear and brief. Lots of long,
275 convoluted questions get deleted before they are completely read!
276 Do not post HTML-encoded messages. Most people on mailing lists simply delete
280 <listitem><para> If you run one of those nifty <quote>I'm on holiday</quote> things when
281 you are away, make sure its configured to not answer mailing list traffic. Autoresponses
282 to mailing lists really irritate the thousands of people who end up having to deal
283 with such bad netiquet bahavior.
287 <indexterm><primary>cross post</primary></indexterm>
288 Don't cross post. Work out which is the best list to post to
289 and see what happens. Do not post to both samba-ntdom and samba-technical.
290 Many people active on the lists subscribe to more
291 than one list and get annoyed to see the same message two or more times.
292 Often someone who thinks a message would be better dealt
293 with on another list will forward it on for you.</para></listitem>
295 <listitem><para>You might include <emphasis>partial</emphasis>
296 log files written at a log level set to as much as 20.
297 Please do not send the entire log but just enough to give the context of the
298 error messages.</para></listitem>
300 <listitem><para>If you have a complete Netmon trace (from the opening of
301 the pipe to the error), you can send the *.CAP file as well.</para></listitem>
303 <listitem><para>Please think carefully before attaching a document to an email.
304 Consider pasting the relevant parts into the body of the message. The Samba
305 mailing lists go to a huge number of people. Do they all need a copy of your
306 &smb.conf; in their attach directory?</para></listitem>
313 <title>How to Get Off the Mailing Lists</title>
315 <para>To have your name removed from a Samba mailing list, go to the same
316 place where you went to
317 subscribe to it, go to <ulink noescape="1" url="http://lists.samba.org/">http://lists.samba.org</ulink>,
318 click on your nearest mirror, click on <command>Support</command>, and
319 then click on <command>Samba-related mailing lists</command>.
323 Please do not post messages to the list asking to be removed. You will only
324 be referred to the above address (unless that process failed in some way).