Difference between revisions of "Samba"
(→Improve throughput: Added option information, set aio read/write size to 1 as recommended upstream)
(→Set and forcing permissions: Added guests share, since this was deleted in previous edit)
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comment = Media share
comment = Media share
valid users = ''greg @pcusers''
valid users = ''greg @pcusers''
force group = ''+pcusers''
force group = ''+pcusers''
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force create mode = 0664
force create mode = 0664
force directory mode = 2775
force directory mode = 2775
Revision as of 13:19, 21 July 2018
Samba is a re-implementation of the SMB networking protocol. It facilitates file and printer sharing among Linux and Windows systems as an alternative to NFS. This article provides instructions for users on how to setup Samba.
- 1 Server
- 1.1 Installation
- 1.2 Usage
- 1.3 Advanced Configuration
- 2 Client
- 2.1 List public shares
- 2.2 NetBIOS/WINS host names
- 2.3 Manual mounting
- 2.4 Automatic mounting
- 2.5 File manager configuration
- 3 Tips and tricks
- 4 Troubleshooting
- 4.1 Failed to start Samba SMB/CIFS server
- 4.2 No dialect specified on mount
- 4.3 Unable to overwrite files, permissions errors
- 4.4 Windows clients keep asking for password even if Samba shares are created with guest permissions
- 4.5 Windows 7 connectivity problems - mount error(12): cannot allocate memory
- 4.6 Windows 10 1709 and up connectivity problems - "Windows cannot access" 0x80004005
- 4.7 Error: Failed to retrieve printer list: NT_STATUS_UNSUCCESSFUL
- 4.8 Sharing a folder fails
- 4.9 "Browsing" network fails with "Failed to retrieve share list from server"
- 4.10 Protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE
- 4.11 Connection to SERVER failed: (Error NT_STATUS_UNSUCCESSFUL)
- 4.12 Connection to SERVER failed: (Error NT_STATUS_CONNECTION_REFUSED)
- 4.13 Protocol negotiation failed: NT_STATUS_CONNECTION_RESET
- 4.14 Password Error when correct credentials are given (error 1326)
- 4.15 Mapping reserved Windows characters
- 4.16 Folder shared inside graphical environment is not available to guests
- 4.17 Mount error: Host is down
- 5 See also
Install the package.
Samba is configured in the
/etc/samba/smb.conf configuration file, which is extensively documented in .
Because thepackage does not provide this file, one needs to create it before starting smbd.
A documented example as in
smb.conf.default from the Samba git repository may be used to setup
- The default configuration sets
log fileto a non-writable location, which will cause errors - change this to the correct location:
log file = /var/log/samba/%m.log.
- If required; the
workgroupspecified in the
[global]section has to match the Windows workgroup (default
smb.conffile, run the command to check for syntactic errors.
Adding a user
Samba requires a Linux user account - you may use an existing user account or create a new one.
guest accountand may be used for shares containing
guest ok = yes, thus preventing the need of user login on that share.
Although the user name is shared with Linux system, Samba uses a password separate from that of the Linux user accounts. Replace
samba_user with the chosen Samba user account:
# smbpasswd -a samba_user
If you want the new user only to be allowed to remotely access the file server shares through Samba, you can restrict other login options：
- disabling shell -
usermod --shell /usr/bin/nologin --lock username
- disabling SSH logons - edit
/etc/ssh/sshd_conf, change option
Also see Security for hardening your system.
Samba users can be listed using thecommand:
# pdbedit -L -v
Changing user password
To change an user password, use
# smbpasswd samba_user
map to guest = Bad Userin the
/etc/samba/smb.conf. A different
guest accountmay be used instead of the default provided
Make sure shares have been proper defined as can be seen in the Share Definitions section of smb.conf.default.
To provide basic file sharing through SMB start/enable
nmb.service services. See the and man pages for details, as the
nmb.service service may not always be required.
"Usershares" is a feature that gives non-root users the capability to add, modify, and delete their own share definitions.
This creates the usershares directory in
# mkdir -p /var/lib/samba/usershares
This creates the group sambashare:
# groupadd -r sambashare
This changes the owner of the directory to root and the group to sambashare:
# chown root:sambashare /var/lib/samba/usershares
This changes the permissions of the usershares directory so that users in the group sambashare can read, write and execute files:
# chmod 1770 /var/lib/samba/usershares
Set the following parameters in the
smb.conf configuration file:
[global] usershare path = /var/lib/samba/usershares usershare max shares = 100 usershare allow guests = yes usershare owner only = yes ...
Add your user to the sambashare group. Replace
your_username with the name of your user:
# gpasswd sambashare -a your_username
Log out and log back in. You should now be able to configure your samba share using GUI. For example, in Thunar you can right click on any directory and share it on the network. If you want to share paths inside your home directory you must make it listable for the group others.
Set and forcing permissions
Permissions may be applied to both the server and shares:
[global] ;inherit owner = unix only ; Inherit ownership of the parent directory for new files and directories ;inherit permissions = yes ; Inherit permissions of the parent directory for new files and directories create mask = 0664 directory mask = 2755 force create mode = 0644 force directory mode = 2755 ... [media] comment = Media share accessible by greg and pcusers path = /path/to/media valid users = greg @pcusers force group = +pcusers public = no writable = yes create mask = 0664 directory mask = 2775 force create mode = 0664 force directory mode = 2775 [public] comment = Public share where archie has write access path = /path/to/public public = yes read only = yes write list = archie printable = no [guests] comment = Allow all users to read/write path = /path/to/guests public = yes only guest = yes writable = yes printable = no
Seefor a full overview of possible permission flags and settings.
Restrict protocols for better security
By default Samba allows the usage of (possible) insecure and out-of-dated protocols for compatible reasons.
server min protocol and
server max protocol in
/etc/samba/smb.conf to force usage of a minimum and maximum protocol:
[global] server min protocol = SMB2 ; server max protocol = SMB3
server max protocolin for an overview of supported protocols.
server min protocol = SMB3when clients should only connect using the latest SMB3 protocol, e.g. on clients running Windows 8 and later.
mount.cifs should specify the correct
# mount -t cifs //SERVER/sharename /mnt/mountpoint -o username=username,password=password,iocharset=utf8,vers=3.1.1
Seefor more information.
Use native SMB transport encryption
Native SMB transport encryption is available in SMB version 3.0 or newer. It is only offered by Samba if
server max protocol is set to
SMB3 or newer. Clients supporting this type of encryption include Windows 8 and newer, Windows server 2012 and newer, and smbclient of Samba 4.1 and newer.
To use native SMB transport encryption by default, set the
smb encrypt parameter globally and/or share. Possible values are off (or disabled), enabled (or auto or if_required), desired, and required (or mandatory). A special value is default which is the implicit default setting of enabled:
[global] ... smb encrypt = required [media] ... smb encrypt = desired
Seefor more information.
When mounting a share, specify
seal mount option to force encryption.
Disable printer sharing
By default Samba share printers configured using CUPS.
If you do not want printers to be shared, use the following settings:
[global] load printers = no printing = bsd printcap name = /dev/null disable spoolss = yes show add printer wizard = no
Samba offers an option to block files with certain patterns, like file extensions. This option can be used to prevent dissemination of viruses or to dissuade users from wasting space with certain files. More information about this option can be found in.
... [myshare] comment = Private path = /mnt/data read only = no veto files = /*.exe/*.com/*.dll/*.bat/*.vbs/*.tmp/*.mp3/*.avi/*.mp4/*.wmv/*.wma/
The default settings should be sufficient for most users. However setting the 'socket options' correct can improve performance, but getting them wrong can degrade it by just as much. Test the effect before making any large changes.
Read theman page before applying any of the options listed below.
The following settings should be append to the
[global] section of
SMB3 multi-channel may improve performance, however it may result in data corruption under some race conditions. Future releases may improve this situation:
server multi channel support = yes
Setting a deadtime is useful to stop a server's resources being exhausted by a large number of inactive connections:
deadtime = 30
The usage of sendfile may make more efficient use of the system CPU's and cause Samba to be faster:
use sendfile = yes
The write cache allows Samba to batch client writes into a more efficient write size for RAID disks (i.e. writes may be tuned to be the RAID stripe size) and can improve performance on systems where the disk subsystem is a bottleneck but there is free memory for userspace programs:
write cache size = 262144
Setting min receivefile size allows zero-copy writes directly from network socket buffers into the filesystem buffer cache (if available). It may improve performance but user testing is recommended:
min receivefile size = 16384
Reading/writing files asynchronously may improve performance instead of using synchronously writes:
aio read size = 1 aio write size = 1
Increasing the receive/send buffers size and socket optimize flags might be useful to improve throughput. It is recommended to test each flag separately as it may cause issues on some networks:
socket options = IPTOS_LOWDELAY TCP_NODELAY IPTOS_THROUGHPUT SO_RCVBUF=131072 SO_SNDBUF=131072
ftp-like command line interface. See for commonly used commands.
For a lightweight alternative (without support for listing public shares, etc.), install that provides
The following command lists public shares on a server:
$ smbclient -L hostname -U%
Alternatively, running smbtree will show a tree diagram of all the shares. This is not advisable on a network with a lot of computers, but can be helpful for diagnosing if you have the correct sharename.
$ smbtree -b -N
Where the options are
--broadcast) to use broadcast instead of using the master browser and
-no-pass) to not ask for a password.
NetBIOS/WINS host names
You may need to start
winbind.service in order to resolve host names with e.g.,
wins to the “hosts” line in
Disable NetBIOS/WINS support
When not using NetBIOS/WINS host name resolution, it may be preferred to disable this protocol:
[global] disable netbios = yes dns proxy = no
Create a mount point for the share:
# mkdir /mnt/mountpoint
Mount the share using
type. Not all the options listed below are needed or desirable:
# mount -t cifs //SERVER/sharename /mnt/mountpoint -o username=username,password=password,workgroup=workgroup,iocharset=utf8,uid=username,gid=group
- If the
gidbeing used does not match the user of the server, the
forcegidoptions may be helpful. However note permissions assigned to a file when
forcegidare in effect may not reflect the the real (server) permissions. See the File And Directory Ownership And Permissions section in for more information.
- To allow users to mount it as long as the mount point resides in a directory controllable by the user; i.e. the user's home, append the
usersmount option. The option is users (plural). For other filesystem types handled by mount, this option is usually user; sans the "s".
gidas mount options may cause I/O errors, it is recommended to set/check correct File permissions and attributes instead.
- The server name.
- The shared directory.
- The local directory where the share will be mounted.
- See for more information.
- Abstain from using a trailing
//SERVER/sharename/will not work.
- If your mount does not work stable, stutters or freezes, try to enable different SMB protocol version with
vers=option. For example,
vers=2.0for Windows Vista mount.
- If having timeouts on a mounted network share with cifs on a shutdown, see WPA supplicant#Problem with mounted network shares (cifs) and shutdown.
Storing passwords in a world readable file is not recommended. A safer method is to use a credentials file instead, e.g. inside
The credential file should explicitly readable/writeable to root:
# chown root:root /etc/samba/credentials # chmod 700 /etc/samba/credentials # chmod 600 /etc/samba/credentials/share
NetworkManager-wait-online.service(depending on your setup) to proper enable booting on start-up.
As mount entry
This is an simple example of a
cifs mount entry that requires authentication:
//SERVER/sharename /mnt/mountpoint cifs username=myuser,password=mypass 0 0
\040(ASCII code for space in octal). For example,
//SERVER/share nameon the command line should be
To speed up the service on boot, add the
x-systemd.automount option to the entry:
//SERVER/SHARENAME /mnt/mountpoint cifs credentials=/path/to/smbcredentials/share,x-systemd.automount 0 0
As systemd unit
Create a new
.mount file inside
mnt-myshare.mountcan only be used if are going to mount the share under
/mnt/myshare. Otherwise the following error might occur:
systemd: mnt-myshare.mount: Where= setting does not match unit name. Refusing..
Requires= replace (if needed) with your Network configuration.
What= path to share
Where= path to mount the share
Options= share mounting options
Wants. This might avoid mount errors at boot time that do not arise when testing the unit.
[Unit] Description=Mount Share at boot Requires=systemd-networkd.service After=network-online.target Wants=network-online.target [Mount] What=//server/share Where=/mnt/myshare Options=credentials=/etc/samba/creds/myshare,iocharset=utf8,rw,x-systemd.automount Type=cifs TimeoutSec=30 [Install] WantedBy=multi-user.target
First, check if you can see all the shares you are interested in mounting:
$ smbtree -U remote_user
If that does not work, find and modify the following line
domain master = auto
If everything works as expected, install from the official repositories.
Then, add the following line to
Now copy the directory
/etc/smbnetfs/.smb to your home directory:
$ cp -a /etc/smbnetfs/.smb ~
Then create a link to
$ ln -sf /etc/samba/smb.conf ~/.smb/smb.conf
If a username and a password are required to access some of the shared folders, edit
to include one or more entries like this:
auth "hostname" "username" "password"
It is also possible to add entries for specific hosts to be mounted by smbnetfs, if necessary.
More details can be found in
When you are done with the configuration, you need to run
$ chmod 600 ~/.smb/smbnetfs.*
Otherwise, smbnetfs complains about 'insecure config file permissions'.
Finally, to mount your Samba network neighbourhood to a directory of your choice, call
$ smbnetfs mount_point
The Arch Linux package also maintains an additional system-wide operation mode for smbnetfs. To enable it, you need to make the
said modifications in the directoy
Then, you can start and/or enable the
smbnetfs daemon as usual. The system-wide mount point is at
See Autofs for information on the kernel-based automounter for Linux.
File manager configuration
GNOME Files, Nemo, Caja, Thunar and PCManFM
In order to access samba shares through GNOME Files, Nemo, Caja, Thunar or PCManFM, install the official repositories.package, available in the
Ctrl+l and enter
smb://servername/share in the location bar to access your share.
The mounted share is likely to be present at
~/.gvfs in the filesystem.
KDE has the ability to browse Samba shares built in. To use a GUI in the KDE System Settings, you will need to install thepackage.
If you get a "Time Out" Error when navigating with Dolphin, you should uncomment and edit the following line in smb.conf:
name resolve order = lmhosts bcast host wins
as shown in this page.
Other graphical environments
There are a number of useful programs, but they may need to have packages created for them. This can be done with the Arch package build system. The good thing about these others is that they do not require a particular environment to be installed to support them, and so they bring along less baggage.
- is available in the official repositories.
- LinNeighborhood, RUmba, xffm-samba plugin for Xffm are not available in the official repositories or the AUR. As they are not officially (or even unofficially supported), they may be obsolete and may not work at all.
Tips and tricks
If nothing is known about other systems on the local network, and automated tools such as smbnetfs are not available, the following methods allow one to manually probe for Samba shares.
1. First, install the and packages.
nmap checks which ports are open:
# nmap -p 139 -sT "192.168.1.*"
In this case, a scan on the 192.168.1.* IP address range and port 139 has been performed, resulting in:
$ nmap -sT "192.168.1.*"
Starting nmap 3.78 ( http://www.insecure.org/nmap/ ) at 2005-02-15 11:45 PHT Interesting ports on 192.168.1.1: (The 1661 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 139/tcp open netbios-ssn 5000/tcp open UPnP Interesting ports on 192.168.1.5: (The 1662 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 6000/tcp open X11 Nmap run completed -- 256 IP addresses (2 hosts up) scanned in 7.255 seconds
The first result is another system; the second happens to be the client from where this scan was performed.
3. Now that systems with port 139 open are revealed, useto check for NetBIOS names:
$ nmblookup -A 192.168.1.1
Looking up status of 192.168.1.1 PUTER <00> - B <ACTIVE> HOMENET <00> - <GROUP> B <ACTIVE> PUTER <03> - B <ACTIVE> PUTER <20> - B <ACTIVE> HOMENET <1e> - <GROUP> B <ACTIVE> USERNAME <03> - B <ACTIVE> HOMENET <1d> - B <ACTIVE> MSBROWSE <01> - <GROUP> B <ACTIVE>
Regardless of the output, look for <20>, which shows the host with open services.
smbclient to list which services are shared on PUTER. If prompted for a password, pressing enter should still display the list:
$ smbclient -L \\PUTER
Sharename Type Comment
---- ------- MY_MUSIC Disk SHAREDDOCS Disk PRINTER$ Disk PRINTER Printer IPC$ IPC Remote Inter Process Communication Server Comment
------- PUTER Workgroup Master
------- HOMENET PUTER
Remote control of Windows computer
Samba offers a set of tools for communication with Windows. These can be handy if access to a Windows computer through remote desktop is not an option, as shown by some examples.
Send shutdown command with a comment:
$ net rpc shutdown -C "comment" -I IPADDRESS -U USERNAME%PASSWORD
A forced shutdown instead can be invoked by changing -C with comment to a single -f. For a restart, only add -r, followed by a -C or -f.
Stop and start services:
$ net rpc service stop SERVICENAME -I IPADDRESS -U USERNAME%PASSWORD
To see all possible net rpc command:
$ net rpc
Failed to start Samba SMB/CIFS server
smb.confon syntactic errors with .
- Set correct permissions for
# chmod 0755 /var/cache/samba/msg
No dialect specified on mount
The client is using an unsupported SMB/CIFS version that is required by the server.
See #Restrict protocols for better security for more information.
Unable to overwrite files, permissions errors
- Append the mount option
msdfs root = noto the
[global]section of the server's
map to guest inside the
global section of
map to guest = Bad User
Windows 7 connectivity problems - mount error(12): cannot allocate memory
A known Windows 7 bug that causes "mount error(12): cannot allocate memory" on an otherwise perfect cifs share on the Linux end can be fixed by setting a few registry keys on the Windows box as follows:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache(set to
Alternatively, start Command Prompt in Admin Mode and execute the following:
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "LargeSystemCache" /t REG_DWORD /d 1 /f reg add "HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" /v "Size" /t REG_DWORD /d 3 /f
Do one of the following for the settings to take effect:
- Restart Windows
- Restart the Server service via services.msc
- From the Command Prompt run: 'net stop lanmanserver' and 'net start lanmanserver' - The server may automatically restart after stopping it.
Windows 10 1709 and up connectivity problems - "Windows cannot access" 0x80004005
This error affects some machines running Windows 10 version 1709 and later. It is not related to SMB1 being disabled in this version but to the fact that Microsoft disabled insecure logons for guests on this version for some, but not others.
To fix, open Group Policy Editor (
gpedit.msc). Navigate to Computer configuration\administrative templates\network\Lanman Workstation > Enable insecure guest logons and enable it.
Alternatively,change the following value in the registry:
Error: Failed to retrieve printer list: NT_STATUS_UNSUCCESSFUL
If you are a home user and using samba purely for file sharing from a server or NAS, you are probably not interested in sharing printers through it. If so, you can prevent this error from occurring by adding the following lines to your
[global] load printers = No printing = bsd printcap name = /dev/null disable spoolss = Yes
Restart the samba service,
smb.service, and then check your logs:
# cat /var/log/samba/smbd.log
and the error should now no longer be appearing.
Sharing a folder fails
It means that while you are sharing a folder from Dolphin (file manager) and everything seems ok at first, after restarting Dolphin the share icon is gone from the shared folder, and also some output like this in terminal (Konsole) output:
‘net usershare’ returned error 255: net usershare: usershares are currently disabled
To fix it, enable usershare as described in #Enable usershares.
And you are using a firewall (iptables) because you do not trust your local (school, university, hotel) network. This may be due to the following: When the smbclient is browsing the local network it sends out a broadcast request on udp port 137. The servers on the network then reply to your client but as the source address of this reply is different from the destination address iptables saw when sending the request for the listing out, iptables will not recognize the reply as being "ESTABLISHED" or "RELATED", and hence the packet is dropped. A possible solution is to add:
iptables -t raw -A OUTPUT -p udp -m udp --dport 137 -j CT --helper netbios-ns
to your iptables setup.
Protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE
The client probably does not have access to shares. Make sure clients' IP address is in
hosts allow = line in
Connection to SERVER failed: (Error NT_STATUS_UNSUCCESSFUL)
You are probably passing wrong server name to
smbclient. To find out the server name, run
hostnamectl on the server and look at "Transient hostname" line
Connection to SERVER failed: (Error NT_STATUS_CONNECTION_REFUSED)
Make sure that the server has started. The shared directories should exist and be accessible.
Protocol negotiation failed: NT_STATUS_CONNECTION_RESET
Probably the server is configured not to accept protocol SMB1. Add option
client max protocol = SMB2 in
Or just pass argument
-m SMB2 to
Password Error when correct credentials are given (error 1326)
Samba 4.5 has NTLMv1 authentication disabled by default. It is recommend to install the latest available upgrades on clients and deny access for unsupported clients.
If you still need support for very old clients without NTLMv2 support (e.g. Windows XP), it is possible force enable NTLMv1, although this is not recommend for security reasons:
[global] lanman auth = yes ntlm auth = yes
If NTLMv2 clients are unable to authenticate when NTLMv1 has been enabled, create the following file on the client:
[global] sec = ntlmv2 client ntlmv2 auth = yes
This change also affects samba shares mounted with mount.cifs. If after upgrade to Samba 4.5 your mount fails, add the sec=ntlmssp option to your mount command, e.g.
mount.cifs //server/share /mnt/point -o sec=ntlmssp,...
See theman page: ntlmssp - Use NTLMv2 password hashing encapsulated in Raw NTLMSSP message. The default in mainline kernel versions prior to v3.8 was sec=ntlm. In v3.8, the default was changed to sec=ntlmssp.
Mapping reserved Windows characters
Starting with kernel 3.18, the cifs module uses the "mapposix" option by default.
When mounting a share using unix extensions and a default Samba configuration, files and directories containing one of the seven reserved Windows characters
: \ * < > ? are listed but cannot be accessed.
Possible solutions are:
- Use the undocumented
nomapposixmount option for cifs
# mount.cifs //server/share /mnt/point -o nomapposix
- Configure Samba to remap
mapposix("SFM", Services for Mac) style characters to the correct native ones using fruit
[global] vfs objects = catia fruit fruit:encoding = native
- Manually remap forbidden characters using catia
[global] vfs objects = catia catia:mappings = 0x22:0xf022, 0x2a:0xf02a, 0x2f:0xf02f, 0x3a:0xf03a, 0x3c:0xf03c, 0x3e:0xf03e, 0x3f:0xf03f, 0x5c:0xf05c, 0x7c:0xf07c, 0x20:0xf020
The latter approach (using catia or fruit) has the drawback of filtering files with unprintable characters.
This section presupposes:
- Usershares are configured following previous section
- A shared folder has been created as a non-root user from GUI
- Guests access has been set to shared folder during creation
- Samba service has been restarted at least once since last
For clarification purpose only, in the following sub-sections is assumed:
- Shared folder is located inside user home directory path (
- Shared folder name is MySharedFiles
- Guest access is read-only.
- Windows users will access shared folder content without login prompt
Verify correct samba configuration
Run the following command from a terminal to test configuration file correctness:
Run the following commands from a terminal:
$ cd /var/lib/samba/usershare $ ls
If everything is fine, you will notice a file named
Read the file contents using the following command:
$ cat mysharedfiles
The terminal output should display something like this:
path=/home/yourUser/Shared comment= usershare_acl=S-1-1-0:r guest_ok=y sharename=MySharedFiles
Verify folder access by guest
Run the following command from a terminal. If prompted for a password, just press Enter:
$ smbclient -L localhost
If everything is fine, MySharedFiles should be displayed under
Run the following command in order to access the shared folder as guest (anonymous login)
$ smbclient -N //localhost/MySharedFiles
If everything is fine samba client prompt will be displayed:
From samba prompt verify guest can list directory contents:
smb: \> ls
NTFS_STATUS_ACCESS_DENIED error displayed, probably there is something to be solved at directory permission level.
Run the following commands as root to set correct permissions for folders:
# cd /home # chmod -R 755 /home/yourUser/Shared
Access shared folder again as guest to be sure guest read access error has been solved.
Mount error: Host is down
This error might be seen when mounting shares of Synology NAS servers. Use the mount option
vers=1.0 to solve it.