Chapter 37. SWAT: The Samba Web Administration Tool
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## Chapter 37. SWAT: The Samba Web Administration Tool

### John H. Terpstra

Samba Team

`<jht@samba.org>`

April 21, 2003

There are many and varied opinions regarding the usefulness of SWAT. No matter how hard one tries to produce the perfect configuration tool, it remains an object of personal taste. SWAT is a tool that allows Web-based configuration of Samba. It has a wizard that may help to get Samba configured quickly, it has context-sensitive help on each `smb.conf` parameter, it provides for monitoring of current state of connection information, and it allows networkwide MS Windows network password management.

## Features and Benefits

SWAT is a facility that is part of the Samba suite. The main executable is called swat and is invoked by the internetworking super daemon. See appropriate section for details.

SWAT uses integral Samba components to locate parameters supported by the particular version of Samba. Unlike tools and utilities that are external to Samba, SWAT is always up to date as known Samba parameters change. SWAT provides context-sensitive help for each configuration parameter, directly from man page entries.

Some network administrators believe that it is a good idea to write systems documentation inside configuration files, and for them SWAT will always be a nasty tool. SWAT does not store the configuration file in any intermediate form; rather, it stores only the parameter settings, so when SWAT writes the `smb.conf` file to disk, it writes only those parameters that are at other than the default settings. The result is that all comments, as well as parameters that are no longer supported, will be lost from the `smb.conf` file. Additionally, the parameters will be written back in internal ordering.

### Note

Before using SWAT, please be warned SWAT will completely replace your `smb.conf` with a fully optimized file that has been stripped of all comments you might have placed there and only nondefault settings will be written to the file.

## Guidelines and Technical Tips

This section aims to unlock the dark secrets behind how SWAT may be made to work, how it can be made more secure, and how to solve internationalization support problems.

### Validate SWAT Installation

The very first step that should be taken before attempting to configure a host system for SWAT operation is to check that it is installed. This may seem a trivial point to some, but several Linux distributions do not install SWAT by default, even though they do ship an installable binary support package containing SWAT on the distribution media.

When you have confirmed that SWAT is installed, it is necessary to validate that the installation includes the binary swat file as well as all the supporting text and Web files. A number of operating system distributions in the past have failed to include the necessary support files, even though the swat binary executable file was installed.

Finally, when you are sure that SWAT has been fully installed, please check that SWAT is enabled in the control file for the internetworking super-daemon (inetd or xinetd) that is used on your operating system platform.

#### Locating the SWAT File

To validate that SWAT is installed, first locate the swat binary file on the system. It may be found under the following directories:

`/usr/local/samba/bin` the default Samba location
`/usr/sbin` the default location on most Linux systems
`/opt/samba/bin`

The actual location is much dependent on the choice of the operating system vendor or as determined by the administrator who compiled and installed Samba.

There are a number of methods that may be used to locate the swat binary file. The following methods may be helpful.

If swat is in your current operating system search path, it will be easy to find it. You can ask what are the command-line options for swat as shown here:

    frodo:~ # swat -?
    Usage: swat [OPTION...]
      -a, --disable-authentication         Disable authentication (demo mode)

    Help options:
      -?, --help                           Show this help message
      --usage                              Display brief usage message

    Common samba options:
      -d, --debuglevel=DEBUGLEVEL          Set debug level
      -s, --configfile=CONFIGFILE          Use alternative configuration file
      -l, --log-basename=LOGFILEBASE       Basename for log/debug files
      -V, --version                        Print version

#### Locating the SWAT Support Files

Now that you have found that swat is in the search path, it is easy to identify where the file is located. Here is another simple way this may be done:

    frodo:~ # whereis swat
    swat: /usr/sbin/swat /usr/share/man/man8/swat.8.gz

If the above measures fail to locate the swat binary, another approach is needed. The following may be used:

    frodo:/ # find / -name swat -print
    /etc/xinetd.d/swat
    /usr/sbin/swat
    /usr/share/samba/swat
    frodo:/ #

This list shows that there is a control file for xinetd, the internetwork super-daemon that is installed on this server. The location of the SWAT binary file is `/usr/sbin/swat`, and the support files for it are located under the directory `/usr/share/samba/swat`.

We must now check where swat expects to find its support files. This can be done as follows:

    frodo:/ # strings /usr/sbin/swat | grep "/swat"
    /swat/
    ...
    /usr/share/samba/swat
    frodo:/ #

The `/usr/share/samba/swat/` entry shown in this listing is the location of the support files. You should verify that the support files exist under this directory. A sample list is as shown:

    jht@frodo:/> find /usr/share/samba/swat -print
    /usr/share/samba/swat
    /usr/share/samba/swat/help
    /usr/share/samba/swat/lang
    /usr/share/samba/swat/lang/ja
    /usr/share/samba/swat/lang/ja/help
    /usr/share/samba/swat/lang/ja/help/welcome.html
    /usr/share/samba/swat/lang/ja/images
    /usr/share/samba/swat/lang/ja/images/home.gif
    ...
    /usr/share/samba/swat/lang/ja/include
    /usr/share/samba/swat/lang/ja/include/header.nocss.html
    ...
    /usr/share/samba/swat/lang/tr
    /usr/share/samba/swat/lang/tr/help
    /usr/share/samba/swat/lang/tr/help/welcome.html
    /usr/share/samba/swat/lang/tr/images
    /usr/share/samba/swat/lang/tr/images/home.gif
    ...
    /usr/share/samba/swat/lang/tr/include
    /usr/share/samba/swat/lang/tr/include/header.html
    /usr/share/samba/swat/using_samba
    ...
    /usr/share/samba/swat/images
    /usr/share/samba/swat/images/home.gif
    ...
    /usr/share/samba/swat/include
    /usr/share/samba/swat/include/footer.html
    /usr/share/samba/swat/include/header.html
    jht@frodo:/>

If the files needed are not available, it is necessary to obtain and install them before SWAT can be used.

### Enabling SWAT for Use

SWAT should be installed to run via the network super-daemon. Depending on which system your UNIX/Linux system has, you will have either an inetd- or xinetd-based system.

The nature and location of the network super-daemon varies with the operating system implementation. The control file (or files) can be located in the file `/etc/inetd.conf` or in the directory `/etc/[x]inet[d].d` or in a similar location.

The control entry for the older style file might be:

    	# swat is the Samba Web Administration Tool
    	swat stream tcp nowait.400 root /usr/sbin/swat swat

A control file for the newer style xinetd could be:

    # default: off
    # description: SWAT is the Samba Web Admin Tool. Use swat \
    #              to configure your Samba server. To use SWAT, \
    #              connect to port 901 with your favorite web browser.
    service swat
    {
    	port    = 901
    	socket_type     = stream
    	wait    = no
    	only_from = localhost
    	user    = root
    	server  = /usr/sbin/swat
    	log_on_failure  += USERID
    	disable = no
    }

In the above, the default setting for `disable` is `yes`. This means that SWAT is disabled. To enable use of SWAT, set this parameter to `no` as shown.

Both of the previous examples assume that the swat binary has been located in the `/usr/sbin` directory. In addition to the above, SWAT will use a directory access point from which it will load its Help files as well as other control information. The default location for this on most Linux systems is in the directory `/usr/share/samba/swat`. The default location using Samba defaults will be `/usr/local/samba/swat`.

Access to SWAT will prompt for a logon. If you log onto SWAT as any non-root user, the only permission allowed is to view certain aspects of configuration as well as access to the password change facility. The buttons that will be exposed to the non-root user are HOME, STATUS, VIEW, and PASSWORD. The only page that allows change capability in this case is PASSWORD.

As long as you log onto SWAT as the user root, you should obtain full change and commit ability. The buttons that will be exposed include HOME, GLOBALS, SHARES, PRINTERS, WIZARD, STATUS, VIEW, and PASSWORD.

### Securing SWAT through SSL

Many people have asked about how to set up SWAT with SSL to allow for secure remote administration of Samba. Here is a method that works, courtesy of Markus Krieger.

Modifications to the SWAT setup are as follows:

1. Install OpenSSL.

2. Generate certificate and private key.

       root# /usr/bin/openssl req -new -x509 -days 365 -nodes -config \
       	/usr/share/doc/packages/stunnel/stunnel.cnf \
       	-out /etc/stunnel/stunnel.pem -keyout /etc/stunnel/stunnel.pem

3. Remove SWAT entry from [x]inetd.

4. Start stunnel.

       root# stunnel -p /etc/stunnel/stunnel.pem -d 901 \
       	 -l /usr/local/samba/bin/swat swat

Afterward, simply connect to SWAT by using the URL https://myhost:901, accept the certificate, and the SSL connection is up.

### Enabling SWAT Internationalization Support

SWAT can be configured to display its messages to match the settings of the language configurations of your Web browser. It will be passed to SWAT in the Accept-Language header of the HTTP request.

To enable this feature:

- Install the proper msg files from the Samba `source/po` directory into $LIBDIR.

- Set your browsers language setting.

The name of the msg file is the same as the language ID sent by the browser. For example, en means English, ja means Japanese, fr means French.

If you do not like some of messages, or there are no msg files for your locale, you can create them simply by copying the en.msg files to the directory for “your language ID.msg” and filling in proper strings to each “msgstr”. For example, in `it.msg`, the msg file for the Italian locale, just set:

    msgid "Set Default"
    msgstr "Imposta Default"

and so on. If you find a mistake or create a new msg file, please email it to us so we will consider it in the next release of Samba. The msg file should be encoded in UTF-8.

Note that if you enable this feature and the display charset is not matched to your browser's setting, the SWAT display may be corrupted. In a future version of Samba, SWAT will always display messages with UTF-8 encoding. You will then not need to set this `smb.conf` file parameter.

## Overview and Quick Tour

SWAT is a tool that may be used to configure Samba or just to obtain useful links to important reference materials such as the contents of this book as well as other documents that have been found useful for solving Windows networking problems.

### The SWAT Home Page

The SWAT title page provides access to the latest Samba documentation. The manual page for each Samba component is accessible from this page, as are the Samba3-HOWTO (this document) as well as the O'Reilly book “Using Samba.”

Administrators who wish to validate their Samba configuration may obtain useful information from the man pages for the diagnostic utilities. These are available from the SWAT home page also. One diagnostic tool that is not mentioned on this page but that is particularly useful is ethereal.

### Warning

SWAT can be configured to run in demo mode. This is not recommended because it runs SWAT without authentication and with full administrative ability. It allows changes to `smb.conf` as well as general operation with root privileges. The option that creates this ability is the `-a` flag to SWAT. Do not use this in a production environment.

### Global Settings

The GLOBALS button exposes a page that allows configuration of the global parameters in `smb.conf`. There are two levels of exposure of the parameters:

- Basic exposes common configuration options.

- Advanced exposes configuration options needed in more complex environments.

To switch to other than Basic editing ability, click on Advanced. You may also do this by clicking on the radio button, then click on the Commit Changes button.

After making any changes to configuration parameters, make sure that you click on the Commit Changes button before moving to another area; otherwise, your changes will be lost.

### Note

SWAT has context-sensitive help. To find out what each parameter is for, simply click on the Help link to the left of the configuration parameter.

### Share Settings

To affect a currently configured share, simply click on the pull-down button between the Choose Share and the Delete Share buttons and select the share you wish to operate on. To edit the settings, click on the Choose Share button. To delete the share, simply press the Delete Share button.

To create a new share, next to the button labeled Create Share, enter into the text field the name of the share to be created, then click on the Create Share button.

### Printers Settings

To affect a currently configured printer, simply click on the pull-down button between the Choose Printer and the Delete Printer buttons and select the printer you wish to operate on. To edit the settings, click on the Choose Printer button. To delete the share, simply press the Delete Printer button.

To create a new printer, next to the button labeled Create Printer, enter into the text field the name of the share to be created, then click on the Create Printer button.

### The SWAT Wizard

The purpose of the SWAT Wizard is to help the Microsoft-knowledgeable network administrator to configure Samba with a minimum of effort.

The Wizard page provides a tool for rewriting the `smb.conf` file in fully optimized format. This will also happen if you press the Commit button. The two differ because the Rewrite button ignores any changes that may have been made, while the Commit button causes all changes to be affected.

The Edit button permits the editing (setting) of the minimal set of options that may be necessary to create a working Samba server.

Finally, there are a limited set of options that determine what type of server Samba will be configured for, whether it will be a WINS server, participate as a WINS client, or operate with no WINS support. By clicking one button, you can elect to expose (or not) user home directories.

### The Status Page

The status page serves a limited purpose. First, it allows control of the Samba daemons. The key daemons that create the Samba server environment are smbd, nmbd, and winbindd.

The daemons may be controlled individually or as a total group. Additionally, you may set an automatic screen refresh timing. As MS Windows clients interact with Samba, new smbd processes are continually spawned. The auto-refresh facility allows you to track the changing conditions with minimal effort.

Finally, the status page may be used to terminate specific smbd client connections in order to free files that may be locked.

### The View Page

The view page allows you to view the optimized `smb.conf` file and, if you are particularly masochistic, permits you also to see all possible global configuration parameters and their settings.

### The Password Change Page

The password change page is a popular tool that allows the creation, deletion, deactivation, and reactivation of MS Windows networking users on the local machine. You can also use this tool to change a local password for a user account.

When logged in as a non-root account, the user must provide the old password as well as the new password (twice). When logged in as root, only the new password is required.

One popular use for this tool is to change user passwords across a range of remote MS Windows servers.

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