20 Samba #

When starting the module for the first time, the Samba Installation dialog starts, prompting you to make a few basic decisions concerning the administration of the server. At the end of the configuration, it prompts for the Samba administrator password (Samba Root Password). For later starts, the Samba Configuration dialog appears.

The Samba Installation dialog consists of two steps and optional detailed settings:

If you do not want to proceed with a detailed server configuration, confirm with OK. Then in the final pop-up box, set the Samba root Password.

You can change all settings later in the Samba Configuration dialog with the Start-Up, Shares, Identity, Trusted Domains, and LDAP Settings tabs.

On clients running current versions of SUSE Linux Enterprise Server or other recent Linux versions, the insecure SMB1/CIFS protocol is disabled by default. However, existing instances of Samba may be configured to only serve shares using the SMB1/CIFS version of the protocol. To interact with such clients, you need to configure Samba to serve shares using at least the SMB 2.1 protocol.

There are setups in which only SMB1 can be used—for example, because they rely on SMB1's/CIFS's Unix extensions. These extensions have not been ported to newer protocol versions. If you are in this situation, consider changing your setup or see Section 20.5.2, “Mounting SMB1/CIFS shares on clients”.

To do so, in the configuration file /etc/samba/smb.conf, set the global parameter server max protocol = SMB2_10. For a list of all possible values, see man smb.conf.

During the first start of the Samba server module, the Samba Configuration dialog appears directly after the two initial steps described in Section 20.4.1.1, “Initial Samba configuration”. Use it to adjust your Samba server configuration.

After editing your configuration, click OK to save your settings.

The following parameters of the [global] section should be modified to match the requirements of your network setup, so other machines can access your Samba server via SMB in a Windows environment.

The following examples illustrate how a CD-ROM drive and the user directories (homes) are made available to the SMB clients.

Warning: Do not share NFS mounts with Samba

Sharing NFS mounts with Samba may result in data loss and is not supported. Install Samba directly on the file server or consider using alternatives, such as iSCSI.

To improve security, each share access can be protected with a password. SMB offers the following ways of checking permissions:

The selection of share, user, server, or domain level security applies to the entire server. It is not possible to offer individual shares of a server configuration with share level security and others with user level security. However, you can run a separate Samba server for each configured IP address on a system.

More information about this subject can be found in the Samba 3 HOWTO. For multiple servers on one system, pay attention to the options interfaces and bind interfaces only.

realmd discovers which domains or realms can be used or configured by checking the DNS SRV records. Ensure that a DNS SRV record is available for the Active Directory domain to be discovered; domain.example.com in the following example:

_ldap._tcp.dc._msdcs.domain.example.com.

The DNS records should be created automatically by the DNS server that comes with the Active Directory.

To discover a particular domain name, run the command:

> sudo realm discover --verbose domain.example.com

* Resolving: _ldap._tcp.dc._msdcs.domain.example.com
 * Sending MS-CLDAP ping to: 192.168.20.10
 * Sending MS-CLDAP ping to: 192.168.12.12
 * Successfully discovered: domain.example.com
...

To join a particular Active Directory domain, run the command:

> sudo realm join --verbose domain.example.com

Once you joined the Active Directory domain, you can configure the machine to enable logging in using the domain accounts. To do so, run:

> sudo realm permit --realm domain.example.com --all

To permit only specific accounts by specifying them in the command as follows:

> sudo realm permit --realm domain.example.com DOMAIN\\USERNAME DOMAIN\\USERNAME

To deny logins from any domain account, use the following command:

> sudo realm deny --realm domain.example.com --all

Snapshots on a Samba server can be exposed to remote Windows clients as previous versions of files or directories.

To enable snapshots on a Samba server, the following conditions must be fulfilled:

To support remote snapshots, you need to modify the /etc/samba/smb.conf file. You can do this either with YaST › Network Services › Samba Server, or manually by enhancing the relevant share section with

vfs objects = snapper

Note that you need to restart the Samba service for manual changes to smb.conf to take effect:

> sudo systemctl restart nmb smb

Figure 20.4: Adding a new Samba share with snapshots enabled #

 

After being configured, snapshots created by Snapper for the Samba share path can be accessed from Windows Explorer from a file or directory's Previous Versions tab.

Figure 20.5: The Previous versions tab in Windows explorer #

 

By default, snapshots can only be created and deleted on the Samba server locally, via the Snapper command line utility, or using Snapper's timeline feature.

Samba can be configured to process share snapshot creation and deletion requests from remote hosts using the File Server Remote VSS Protocol (FSRVP).

In addition to the configuration and prerequisites documented in Section 20.8.3.1, “Previous versions”, the following global configuration is required in /etc/samba/smb.conf:

[global]
rpc_daemon:fssd = fork
registry shares = yes
include = registry

FSRVP clients, including Samba's rpcclient and Windows Server 2012 DiskShadow.exe, can then instruct Samba to create or delete a snapshot for a given share, and expose the snapshot as a new share.

The samba-client package contains an FSRVP client that can remotely request a Windows/Samba server to create and expose a snapshot of a given share. You can then use existing tools in SUSE Linux Enterprise Server to mount the exposed share and back up its files. Requests to the server are sent using the rpcclient binary.

# rpcclient -U 'EXAMPLE\Administrator' ncacn_np:win-server.example.com[ndr64,sign]
Enter EXAMPLE/Administrator's password:

# rpcclient $> netshareenum
netname: windows_server_2012_share
remark:
path:   C:\Shares\windows_server_2012_share
password:       (null)

# rpcclient $> fss_is_path_sup windows_server_2012_share \
UNC \\WIN-SERVER\windows_server_2012_share\ supports shadow copy requests

# rpcclient $> fss_create_expose backup ro windows_server_2012_share
13fe880e-e232-493d-87e9-402f21019fb6: shadow-copy set created
13fe880e-e232-493d-87e9-402f21019fb6(1c26544e-8251-445f-be89-d1e0a3938777): \
\\WIN-SERVER\windows_server_2012_share\ shadow-copy added to set
13fe880e-e232-493d-87e9-402f21019fb6: prepare completed in 0 secs
13fe880e-e232-493d-87e9-402f21019fb6: commit completed in 1 secs
13fe880e-e232-493d-87e9-402f21019fb6(1c26544e-8251-445f-be89-d1e0a3938777): \
share windows_server_2012_share@{1C26544E-8251-445F-BE89-D1E0A3938777} \
exposed as a snapshot of \\WIN-SERVER\windows_server_2012_share\

# rpcclient $> netshareenum
netname: windows_server_2012_share
remark:
path:   C:\Shares\windows_server_2012_share
password:       (null)

netname: windows_server_2012_share@{1C26544E-8251-445F-BE89-D1E0A3938777}
remark: (null)
path:   \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy{F6E6507E-F537-11E3-9404-B8AC6F927453}\Shares\windows_server_2012_share\
password:       (null)

# rpcclient $> fss_delete windows_server_2012_share \
13fe880e-e232-493d-87e9-402f21019fb6 1c26544e-8251-445f-be89-d1e0a3938777
13fe880e-e232-493d-87e9-402f21019fb6(1c26544e-8251-445f-be89-d1e0a3938777): \
\\WIN-SERVER\windows_server_2012_share\ shadow-copy deleted

# rpcclient $> netshareenum
netname: windows_server_2012_share
remark:
path:   C:\Shares\windows_server_2012_share
password:       (null)

You can manage snapshots of SMB shares on the Linux Samba server from Windows clients as well. Windows Server 2012 includes the DiskShadow.exe utility which can manage remote shares similarly to the rpcclient command described in Section 20.8.3.3, “Managing snapshots remotely from Linux with rpcclient”. Note that you need to carefully set up the Samba server first.

The following is an example procedure to set up the Samba server so that the Windows client can manage its shares' snapshots. Note that EXAMPLE is the Active Directory domain used in the testing environment, fsrvp-server.example.com is the host name of the Samba server, and /srv/smb is the path to the SMB share.