## Using Samba

Robert Eckstein, David Collier-Brown, Peter Kelly
1st Edition November 1999
1-56592-449-5, Order Number: 4495
416 pages, $34.95

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Table of Contents

| Appendix A Configuring Samba with SSL |

> ## A.5 SSL Configuration Options

> Table A.1 summarizes the configuration options introduced in the previous section for using SSL. Note that all of these options are global in scope; in other words, they must appear in the `[global]` section of the configuration file.

> Table A.1: SSL Configuration Options
> Option | Parameters | Function | Default | Scope
> --- | --- | --- | --- | ---
> `ssl` | boolean | Indicates whether SSL mode is enabled with Samba. | `no` | Global
> `ssl hosts` | string (list of addresses) | Specifies a list of hosts that must always connect using SSL. | None | Global
> `ssl hosts resign` | string (list of addresses) | Specifies a list of hosts that never connect using SS. | None | Global
> `ssl CA certDir` | string (fully-qualified pathname) | Specifies the directory where the certificates are stored. | None | Global
> `ssl CA certFile` | string (fully-qualified pathname) | Specifies a file that contains all of the certificates for Samba. | None | Global
> `ssl server cert` | string (fully-qualified pathname) | Specifies the location of the server's certificate. | None | Global
> `ssl server key` | string (fully-qualified pathname) | Specifies the location of the server's private key. | None | Global
> `ssl client cert` | string (fully-qualified pathname) | Specifies the location of the client's certificate. | None | Global
> `ssl client key` | string (fully-qualified pathname) | Specifies the location of the client's private key. | None | Global
> `ssl require clientcert` | boolean | Indicates whether Samba should require each client to have a certificate. | `no` | Global
> `ssl require servercert` | boolean | Indicates whether the server itself should have a certificate. | `no` | Global
> `ssl ciphers` | String | Specifies the cipher suite to use during protocol negotiation. | None | Global
> `ssl version` | `ssl2or3`, `ssl3`, or `tls1` | Specifies the version of SSL to use. | `ssl2or3` | Global
> `ssl compatibility` | boolean | Indicates whether compatibility with other implementations of SSL should be activated. | `no` | Global

> ### A.5.1 ssl

> This global option configures Samba to use SSL for communication between itself and clients. The default value of this option is `no`. You can reset it as follows:

>     [global]
>     	ssl = yes

> Note that in order to use this option, you must have a proxy for Windows 95/98 clients, such as in the model presented earlier in this chapter.

> ### A.5.2 ssl hosts

> This option specifies the hosts that will be forced into using SSL. The syntax for specifying hosts and addresses is the same as the `hosts` `allow` and the `hosts` `deny` configuration options. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.

> This example specifies that all hosts that fall into the 192.168.220 subnet must use SSL connections with the client. This type of structure is useful if you know that various connections will be made by a subnet that lies across an untrusted network, such as the Internet. If neither this option nor the `ssl` `hosts` `resign` option has been specified, and `ssl` is set to `yes`, Samba will allow only SSL connections from all clients.

> ### A.5.3 ssl hosts resign

> This option specifies the hosts that will not be forced into SSL mode. The syntax for specifying hosts and addresses is the same as the `hosts` `allow` and the `hosts` `deny` configuration options. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts resign = 160.2.310. 160.2.320.

> This example specifies that all hosts that fall into the 160.2.310 or 160.2.320 subnets will not use SSL connections with the client. If neither this option nor the `ssl` `hosts` option has been specified, and `ssl` is set to `yes`, Samba will allow only SSL connections from all clients.

> ### A.5.4 ssl CA certDir

> This option specifies the directory containing the certificate authority's certificates that Samba will use to authenticate clients. There must be one file in this directory for each certificate authority, named as specified earlier in this chapter. Any other files in this directory are ignored. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.
>     	ssl CA certDir = /usr/local/samba/cert

> There is no default for this option. You can alternatively use the option `ssl` `CA` `certFile` if you wish to place all the certificate authority information in the same file.

> ### A.5.5 ssl CA certFile

> This option specifies a file that contains the certificate authority's certificates that Samba will use to authenticate clients. This option differs from `ssl` `CA` `certDir` in that there is only one file used for all the certificate authorities. An example of its usage follows:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.
>     	ssl CA certFile = /usr/local/samba/cert/certFile

> There is no default for this option. You can also use the option `ssl` `CA` `certDir` if you wish to have a separate file for each certificate authority that Samba trusts.

> ### A.5.6 ssl server cert

> This option specifies the location of the server's certificate. This option is mandatory; the server must have a certificate in order to use SSL. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.
>     	ssl CA certFile = /usr/local/samba/cert/certFile
>     	ssl server cert = /usr/local/samba/private/server.pem

> There is no default for this option. Note that the certificate may contain the private key for the server.

> ### A.5.7 ssl server key

> This option specifies the location of the server's private key. You should ensure that the location of the file cannot be accessed by anyone other than `root`. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.
>     	ssl CA certFile = /usr/local/samba/cert/certFile
>     	ssl server key = /usr/local/samba/private/samba.pem

> There is no default for this option. Note that the private key may be contained in the certificate for the server.

> ### A.5.8 ssl client cert

> This option specifies the location of the client's certificate. The certificate may be requested by the Samba server with the `ssl` `require` `clientcert` option; the certificate is also used by smbclient. For example:

>     [global]
>         ssl = yes
>         ssl hosts = 192.168.220.
>         ssl CA certFile = /usr/local/samba/cert/certFile
>         ssl server cert = /usr/local/ssl/private/server.pem
>         ssl client cert= /usr/local/ssl/private/clientcert.pem

> There is no default for this option.

> ### A.5.9 ssl client key

> This option specifies the location of the client's private key. You should ensure that the location of the file cannot be accessed by anyone other than `root`. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.
>     	ssl CA certDir = /usr/local/samba/cert/
>     	ssl server key = /usr/local/ssl/private/samba.pem
>     	ssl client key = /usr/local/ssl/private/clients.pem

> There is no default for this option. This option is only needed if the client has a certificate.

> ### A.5.10 ssl require clientcert

> This option specifies whether the client is required to have a certificate. The certificates listed with either the `ssl` `CA` `certDir` or the `ssl` `CA` `certFile` will be searched to confirm that the client has a valid certificate and is authorized to connect to the Samba server. The value of this option is a simple boolean. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.
>     	ssl CA certFile = /usr/local/samba/cert/certFile
>     	ssl require clientcert = yes

> We recommend that you require certificates from all clients that could be connecting to the Samba server. The default value for this option is `no`.

> ### A.5.11 ssl require servercert

> This option specifies whether the server is required to have a certificate. Again, this will be used by the smbclient program. The value of this option is a simple boolean. For example:

>     [global]
>     	ssl = yes
>     	ssl hosts = 192.168.220.
>     	ssl CA certFile = /usr/local/samba/cert/certFile
>     	ssl require clientcert = yes
>     	ssl require servercert = yes

> Although we recommend that you require certificates from all clients that could be connecting to the Samba server, a server certificate is not required. It is, however, recommended. The default value for this option is `no`.

> ### A.5.12 ssl ciphers

> This option sets the ciphers on which SSL will decide during the negotiation phase of the SSL connection. Samba can use any of the following ciphers:

>     DEFAULT
>     DES-CFB-M1
>     NULL-MD5
>     RC4-MD5
>     EXP-RC4-MD5
>     RC2-CBC-MD5
>     EXP-RC2-CBC-MD5
>     IDEA-CBC-MD5
>     DES-CBC-MD5
>     DES-CBC-SHA
>     DES-CBC3-MD5
>     DES-CBC3-SHA
>     RC4-64-MD5
>     NULL

> It is best not to set this option unless you are familiar with the SSL protocol and want to mandate a specific cipher suite.

> ### A.5.13 ssl version

> This global option specifies the version of SSL that Samba will use when handling encrypted connections. The default value is `ssl2or3`, which specifies that either version 2 or 3 of the SSL protocol can be used, depending on which version is negotiated in the handshake between the server and the client. However, if you want Samba to use only a specific version of the protocol, you can specify the following:

>     [global]
>     	ssl version = ssl3

> Again, it is best not to set this option unless you are familiar with the SSL protocol and want to mandate a specific version.

> ### A.5.14 ssl compatibility

> This global option specifies whether Samba should be configured to use other versions of SSL. However, because no other versions exist at this writing, the issue is moot and the variable should always be left at the default.

A.4 Setting Up SSL Proxy |  | B. Samba Performance Tuning

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