pdb: Fix array overrun by one.

[Samba/bjacke.git] / docs-xml / Samba3-HOWTO / TOSHARG-Diagnosis.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
<chapter id="diagnosis">
<chapterinfo>
        &author.tridge;
        &author.jelmer;
        &author.danshearer;
        <pubdate>Wed Jan 15</pubdate>
</chapterinfo>

<title>The Samba Checklist</title>

<sect1>
<title>Introduction</title>

<para>
<indexterm><primary>validate</primary></indexterm>
This file contains a list of tests you can perform to validate your
Samba server. It also tells you what the likely cause of the problem
is if it fails any one of these steps. If it passes all these tests,
then it is probably working fine.
</para>

<para>
You should do all the tests in the order shown. We have tried to
carefully choose them so later tests only use capabilities verified in
the earlier tests. However, do not stop at the first error: there
have been some instances when continuing with the tests has helped
to solve a problem.
</para>

<para>
If you send one of the Samba mailing lists  an email saying, <quote>It does not work,</quote>
and you have not followed this test procedure, you should not be surprised
if your email is ignored.
</para>

</sect1>

<sect1>
<title>Assumptions</title>

<para>
In all of the tests, it is assumed you have a Samba server called 
BIGSERVER and a PC called ACLIENT, both in workgroup TESTGROUP.
</para>

<para>
The procedure is similar for other types of clients.
</para>

<para>
It is also assumed you know the name of an available share in your
&smb.conf;. I for our examples this share is called <smbconfsection name="tmp"/>.
You can add a <smbconfsection name="tmp"/> share like this by adding the
lines shown in <link linkend="tmpshare">the next example</link>.
</para>

<example id="tmpshare">
<title>smb.conf with [tmp] Share</title>
<smbconfblock>
<smbconfsection name="[tmp]"/>
<smbconfoption name="comment">temporary files </smbconfoption>
<smbconfoption name="path">/tmp</smbconfoption>
<smbconfoption name="read only">yes</smbconfoption>
</smbconfblock>
</example>

<note><para>
These tests assume version 3.0.0 or later of the Samba suite.
Some commands shown did not exist in earlier versions. 
</para></note>

<para>
<indexterm><primary>error messages</primary></indexterm>
<indexterm><primary>name resolution</primary></indexterm>
<indexterm><primary>/etc/resolv.conf</primary></indexterm>
Please pay attention to the error messages you receive. If any error message
reports that your server is being unfriendly, you should first check that your
IP name resolution is correctly set up. Make sure your <filename>/etc/resolv.conf</filename>
file points to name servers that really do exist.
</para>

<para>
<indexterm><primary>DNS server access</primary></indexterm>
<indexterm><primary>name resolution</primary></indexterm>
<indexterm><primary>dns proxy</primary></indexterm>
<indexterm><primary>testparm</primary></indexterm>
Also, if you do not have DNS server access for name resolution, please check
that the settings for your &smb.conf; file results in <parameter>dns proxy = no</parameter>. The
best way to check this is with <command>testparm smb.conf</command>.
</para>


<para>
<indexterm><primary>log files</primary></indexterm>
<indexterm><primary>tail</primary></indexterm>
<indexterm><primary>/usr/local/samba/var</primary></indexterm>
<indexterm><primary>/var/log/samba</primary></indexterm>
<indexterm><primary>log files</primary><secondary>monitoring</secondary></indexterm>
It is helpful to monitor the log files during testing by using the
<command>tail -F log_file_name</command> in a separate
terminal console (use ctrl-alt-F1 through F6 or multiple terminals in X). 
Relevant log files can be found (for default installations) in
<filename>/usr/local/samba/var</filename>. Also, connection logs from
machines can be found here or possibly in <filename>/var/log/samba</filename>,
depending on how or if you specified logging in your &smb.conf; file.
</para>

<para>
If you make changes to your &smb.conf; file while going through these test,
remember to restart &smbd; and &nmbd;.
</para>

</sect1>

<sect1>
<title>The Tests</title>
<procedure>
<title>Diagnosing Your Samba Server</title>


<step performance="required">
<para>
<indexterm><primary>testparm</primary></indexterm>
In the directory in which you store your &smb.conf; file, run the command
<command>testparm smb.conf</command>. If it reports any errors, then your &smb.conf;
configuration file is faulty.
</para>

<note><para>
<indexterm><primary>/etc/samba</primary></indexterm>
<indexterm><primary>/usr/local/samba/etc</primary></indexterm>
Your &smb.conf; file may be located in <filename>/etc/samba</filename>
or in <filename>/usr/local/samba/etc</filename>.
</para></note>
</step>

<step performance="required">
<para>
<indexterm><primary>ping</primary></indexterm>
Run the command <command>ping BIGSERVER</command> from the PC and
<command>ping ACLIENT</command> from the UNIX box. If you do not get a valid response,
then your TCP/IP software is not correctly installed. 
</para>

<para>
You will need to start a <quote>DOS prompt</quote> window on the PC to run ping.
</para>

<para>
<indexterm><primary>/etc/hosts</primary></indexterm>
<indexterm><primary>DNS</primary></indexterm>
<indexterm><primary>/etc/resolv.conf</primary></indexterm>
If you get a message saying <quote><errorname>host not found</errorname></quote> or a similar message, then
your DNS software or <filename>/etc/hosts</filename> file is not correctly set up.  If using DNS, check that
the <filename>/etc/resolv.conf</filename> has correct, current, entries in it. It is possible to run
Samba without DNS entries for the server and client, but it is assumed you do have correct entries for the
remainder of these tests.
</para>

<para>
<indexterm><primary>firewall</primary></indexterm>
<indexterm><primary>iptables</primary></indexterm>
<indexterm><primary>ipchains</primary></indexterm>
Another reason why ping might fail is if your host is running firewall 
software. You will need to relax the rules to let in the workstation
in question, perhaps by allowing access from another subnet (on Linux
this is done via the appropriate firewall maintenance commands <command>ipchains</command>
or <command>iptables</command>).
</para>

<note>
<para>
Modern Linux distributions install ipchains/iptables by default. 
This is a common problem that is often overlooked.
</para>
</note>

<para>
<indexterm><primary>iptables</primary></indexterm>
<indexterm><primary>ipchains</primary></indexterm>
If you wish to check what firewall rules may be present in a system under test, simply run
<command>iptables -L -v</command>, or if <parameter>ipchains</parameter>-based firewall rules are in use,
<command>ipchains -L -v</command>.
</para>

<para>
Here is a sample listing from a system that has an external Ethernet interface (eth1) on which Samba
is not active and an internal (private network) interface (eth0) on which Samba is active:
<screen>
frodo:~ # iptables -L -v
Chain INPUT (policy DROP 98496 packets, 12M bytes)
 pkts bytes target     prot opt in     out     source     destination
 187K  109M ACCEPT     all  --  lo     any     anywhere   anywhere
 892K  125M ACCEPT     all  --  eth0   any     anywhere   anywhere
1399K 1380M ACCEPT     all  --  eth1   any     anywhere   anywhere  \
                                        state RELATED,ESTABLISHED

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source     destination
 978K 1177M ACCEPT     all  --  eth1   eth0    anywhere   anywhere \
                                        state RELATED,ESTABLISHED
 658K   40M ACCEPT     all  --  eth0   eth1    anywhere   anywhere
    0     0 LOG        all  --  any    any     anywhere   anywhere \
                                        LOG level warning

Chain OUTPUT (policy ACCEPT 2875K packets, 1508M bytes)
 pkts bytes target     prot opt in     out     source     destination

Chain reject_func (0 references)
 pkts bytes target     prot opt in     out     source     destination
</screen>
</para>

</step>

<step performance="required">
<para>
Run the command <command>smbclient -L BIGSERVER</command>
on the UNIX box. You should get back a list of available shares. 
</para>

<para>
<indexterm><primary>bad password</primary></indexterm>
<indexterm><primary>hosts allow</primary></indexterm>
<indexterm><primary>hosts deny</primary></indexterm>
<indexterm><primary>valid users</primary></indexterm>
<indexterm><primary>guest account</primary></indexterm>
<indexterm><primary>invalid users</primary></indexterm>
If you get an error message containing the string <quote>bad password</quote>, then
you probably have either an incorrect <parameter>hosts allow</parameter>, 
<parameter>hosts deny</parameter>, or <parameter>valid users</parameter> line in your 
&smb.conf;, or your guest account is not valid. Check what your guest account is using &testparm; and
temporarily remove any <parameter>hosts allow</parameter>, <parameter>hosts deny</parameter>,
<parameter>valid users</parameter>, or <parameter>invalid users</parameter> lines.
</para>

<para>
<indexterm><primary>inetd.conf</primary></indexterm>
If you get a message <literal>connection refused</literal> response, then the <command>smbd</command> server may
not be running. If you installed it in <filename>inetd.conf</filename>, then you probably edited
that file incorrectly. If you installed it as a daemon, then check that
it is running and check that the netbios-ssn port is in a LISTEN
state using <command>netstat -a</command>.
</para>

<note><para>
<indexterm><primary>inetd</primary></indexterm>
<indexterm><primary>xinetd</primary><see>inetd</see></indexterm>
Some UNIX/Linux systems use <command>xinetd</command> in place of
<command>inetd</command>. Check your system documentation for the location
of the control files for your particular system implementation of
the network super daemon.
</para></note>

<para>
If you get a message saying <literal>session request failed,</literal> the server refused the
connection. If it says <quote>Your server software is being unfriendly,</quote> then
it's probably because you have invalid command line parameters to &smbd;,
or a similar fatal problem with the initial startup of &smbd;. Also
check your config file (&smb.conf;) for syntax errors with &testparm;
and that the various directories where Samba keeps its log and lock
files exist.
</para>

<para>
There are a number of reasons for which smbd may refuse or decline
a session request. The most common of these involve one or more of
the &smb.conf; file entries as shown in <link linkend="modif1">the next example</link>.
</para>


<example id="modif1">
<title>Configuration for Allowing Connections Only from a Certain Subnet</title>
<smbconfblock>
<smbconfsection name="[globals]"/>
<smbconfoption name="hosts deny">ALL</smbconfoption>
<smbconfoption name="hosts allow">xxx.xxx.xxx.xxx/yy</smbconfoption>
<smbconfoption name="interfaces">eth0</smbconfoption>
<smbconfoption name="bind interfaces only">Yes</smbconfoption>
</smbconfblock>
</example>

<para>
<indexterm><primary>loopback adapter</primary></indexterm>
In <link linkend="modif1">Configuration for Allowing Connections Only from a Certain Subnet</link>, no
allowance has been made for any session requests that will automatically translate to the loopback adapter
address 127.0.0.1.  To solve this problem, change these lines as shown in <link linkend="modif2">the following
example</link>.
</para>

<example id="modif2">
<title>Configuration for Allowing Connections from a Certain Subnet and localhost</title>
<smbconfblock>
<smbconfsection name="[globals]"/>
<smbconfoption name="hosts deny">ALL</smbconfoption>
<smbconfoption name="hosts allow">xxx.xxx.xxx.xxx/yy 127.</smbconfoption>
<smbconfoption name="interfaces">eth0 lo</smbconfoption>
</smbconfblock>
</example>

<para>
<indexterm><primary>inetd</primary></indexterm>
<indexterm><primary>smbclient</primary></indexterm>
Another common cause of these two errors is having something already running on port <constant>139</constant>,
such as Samba (&smbd; is running from <application>inetd</application> already) or Digital's Pathworks. Check
your <filename>inetd.conf</filename> file before trying to start &smbd; as a daemon &smbmdash; it can avoid a
lot of frustration!
</para>

<para>
<indexterm><primary>subnet mask</primary></indexterm>
<indexterm><primary>broadcast address</primary></indexterm>
<indexterm><primary>log.nmbd</primary></indexterm>
<indexterm><primary>network interface</primary></indexterm>
<indexterm><primary>IP address</primary></indexterm>
And yet another possible cause for failure of this test is when the subnet mask and/or broadcast address
settings are incorrect. Please check that the network interface IP address/broadcast address/subnet mask
settings are correct and that Samba has correctly noted these in the <filename>log.nmbd</filename> file.
</para>

</step>

<step performance="required">

<para>
<indexterm><primary>nmblookup</primary></indexterm>
Run the command <command>nmblookup -B BIGSERVER __SAMBA__</command>.
You should get back the IP address of your Samba server.
</para>

<para>
<indexterm><primary>inetd.conf</primary></indexterm>
<indexterm><primary>nmbd</primary></indexterm>
<indexterm><primary>port 137</primary></indexterm>
If you do not, then &nmbd; is incorrectly installed. Check your <filename>inetd.conf</filename>
if you run it from there, or that the daemon is running and listening to UDP port 137.
</para>

<para>
One common problem is that many inetd implementations can't take many
parameters on the command line. If this is the case, then create a
one-line script that contains the right parameters and run that from
inetd.
</para>

</step>

<step performance="required">

<para>
<indexterm><primary>nmblookup</primary></indexterm>
Run the command <command>nmblookup -B ACLIENT `*'</command>.
</para>

<para>
You should get the PC's IP address back. If you do not, then the client
software on the PC isn't installed correctly, or isn't started, or you
got the name of the PC wrong. 
</para>

<para>
If ACLIENT does not resolve via DNS, then use the IP address of the
client in the above test.
</para>

</step>

<step performance="required">

<para>
Run the command <command>nmblookup -d 2 `*'</command>.
</para>

<para>
This time we are trying the same as the previous test but are trying
it via a broadcast to the default broadcast address. A number of
NetBIOS/TCP/IP hosts on the network should respond, although Samba may
not catch all of the responses in the short time it listens. You
should see the <literal>got a positive name query response</literal>
messages from several hosts.
</para>

<para>
<indexterm><primary>nmblookup</primary></indexterm>
If this does not give a result similar to the previous test, then nmblookup isn't correctly getting your
broadcast address through its automatic mechanism. In this case you should experiment with the <smbconfoption
name="interfaces"/> option in &smb.conf; to manually configure your IP address, broadcast, and netmask.
</para>

<para>
If your PC and server aren't on the same subnet, then you will need to use the
<option>-B</option> option to set the broadcast address to that of the PC's subnet.
</para>

<para>
This test will probably fail if your subnet mask and broadcast address are
not correct. (Refer to test 3 notes above).
</para>

</step>

<step performance="required">


<para>
<indexterm><primary>smbclient</primary></indexterm>
Run the command <command>smbclient //BIGSERVER/TMP</command>. You should 
then be prompted for a password. You should use the password of the account
with which you are logged into the UNIX box. If you want to test with
another account, then add the <option>-U accountname</option> option to the end of
the command line &smbmdash; for example, <command>smbclient //bigserver/tmp -Ujohndoe</command>.
</para>

<note><para>
It is possible to specify the password along with the username as follows:
<command>smbclient //bigserver/tmp -Ujohndoe%secret</command>.
</para></note>

<para>
Once you enter the password, you should get the <prompt>smb></prompt> prompt. If you
do not, then look at the error message. If it says <quote><errorname>invalid network
name,</errorname></quote> then the service <smbconfsection name="tmp"/> is not correctly set up in your &smb.conf;.
</para>

<para>
If it says <quote><errorname>bad password,</errorname></quote> then the likely causes are:
</para>

<orderedlist>
<listitem>
        <para>
        Password encryption is enabled by default, but you have not
        yet set a password for your samba user. Run
        <command>smbpasswd -a username</command>
        </para>
</listitem>

<listitem>
        <para>
        Your <smbconfoption name="valid users"/> configuration is incorrect.
        </para>
</listitem>

<listitem>
        <para>
        You have explicitly disabled encrypted passwords with
        <smbconfoption name="encrypt passwords">no</smbconfoption> have a mixed-case password and you haven't enabled the <smbconfoption name="password level"/> option at a high enough level.
        </para>
</listitem>

<listitem>
        <para>
        The <smbconfoption name="path"/> line in &smb.conf; is incorrect. Check it with &testparm;.
        </para>
</listitem>

</orderedlist>

<para>
<indexterm><primary>dir</primary></indexterm>
<indexterm><primary>get</primary></indexterm>
<indexterm><primary>put</primary></indexterm>
<indexterm><primary>help command</primary></indexterm>
Once connected, you should be able to use the commands <command>dir</command>, <command>get</command>,
<command>put</command>, and so on. Type <command>help command</command> for instructions. You should
especially check that the amount of free disk space shown is correct when you type <command>dir</command>.
</para>

</step>

<step performance="required">

<para>
<indexterm><primary>net view</primary></indexterm>
On the PC, type the command <command>net view \\BIGSERVER</command>. You will 
need to do this from within a DOS prompt window. You should get back a 
list of shares available on the server.
</para>

<para>
<indexterm><primary>nmbd</primary></indexterm>
If you get a message <literal>network name not found</literal> or similar error, then NetBIOS
name resolution is not working. This is usually caused by a problem in <command>nmbd</command>.
To overcome it, you could do one of the following (you only need to choose one of them):
</para>

<orderedlist>
<listitem><para>
        Fix the &nmbd; installation.
</para></listitem>

<listitem><para>
        Add the IP address of BIGSERVER to the <command>wins server</command> box in the
        advanced TCP/IP setup on the PC.
</para></listitem>

<listitem><para>
        Enable Windows name resolution via DNS in the advanced section of the TCP/IP setup.
</para></listitem>

<listitem><para>
        Add BIGSERVER to your lmhosts file on the PC.
</para></listitem>
</orderedlist>

<para>
If you get a message <quote><errorname>invalid network name</errorname></quote> or 
<quote><errorname>bad password error,</errorname></quote> then apply the
same fixes as for the <command>smbclient -L</command> test. In
particular, make sure your <command>hosts allow</command> line is correct (see the man pages).
</para>

<para>
Also, do not overlook that fact that when the workstation requests the
connection to the Samba server, it will attempt to connect using the 
name with which you logged onto your Windows machine. You need to make
sure that an account exists on your Samba server with that exact same
name and password.
</para>

<para>
If you get a message <quote><errorname>specified computer is not receiving requests</errorname></quote> or similar error,
it probably means that the host is not contactable via TCP services.
Check to see if the host is running TCP wrappers, and if so, add an entry in
the <filename>hosts.allow</filename> file for your client (or subnet, and so on.)
</para>

</step>

<step performance="required">

<para>
Run the command <command>net use x: \\BIGSERVER\TMP</command>. You should 
be prompted for a password, then you should get a <computeroutput>command completed 
successfully</computeroutput> message. If not, then your PC software is incorrectly 
installed or your &smb.conf; is incorrect. Make sure your <parameter>hosts allow</parameter>
and other config lines in &smb.conf; are correct.
</para>

<para>
By default, most clients only sends encrypted passwords 
and you have <smbconfoption name="encrypt passwords">no</smbconfoption> in &smb.conf;.
Change this setting to `yes' to fix this.
</para>

</step>

<step performance="required">

<para>
Run the command <command>nmblookup -M <parameter>testgroup</parameter></command> where 
<parameter>testgroup</parameter> is the name of the workgroup that your Samba server and 
Windows PCs belong to. You should get back the IP address of the 
master browser for that workgroup.
</para>

<para>
If you do not, then the election process has failed. Wait a minute to
see if it is just being slow, then try again. If it still fails after
that, then look at the browsing options you have set in &smb.conf;. Make
sure you have <smbconfoption name="preferred master">yes</smbconfoption> to ensure that 
an election is held at startup.
</para>

</step>

<step performance="required">

<para>
From file manager, try to browse the server. Your Samba server should
appear in the browse list of your local workgroup (or the one you
specified in &smb.conf;). You should be able to double-click on the name
of the server and get a list of shares. If you get the error message <quote>invalid password,</quote>
your client may be refusing to browse a server that has no encrypted password
capability. In this case make sure <smbconfoption name="encrypt passwords"/> is
set to <quote>yes</quote> and repeat the steps in this gude.
</para>

</step>
</procedure>
</sect1>

</chapter>