Samba

Samba is a free and open-source implementation of SMB/CIFS. As of version 3, Samba provides file and print services over network which can be accessed by Windows, Unix and MacOS X clients. Alternatives are NFS and SSHFS.

:!: It is hence strongly recommended that you use LuCI to establish the initial configuration and then edit the template file (/etc/samba/smb.conf.template) via LuCI Edit Template tab or from the shell as needed.

If luci-app-samba not working or can't find in web gui - > type "rm /tmp/luci-indexcache" or restart router.

Preparations

Prerequisites

Presuming you want to connect a USB harddisc to the device and then access its contents over the cifs protocol, you need to hook up that drive first:

  1. usb.essentials obtain basic support for the USB.
  2. usb.storage obtain support for USB storage and mount local filesystem
  3. Configure /etc/config/firewall to open the following ports (if your LAN access is rejected by default):
    • TCP 137 - NetBIOS Name Service
    • TCP 138 - NETBIOS Datagram Service
    • TCP 139 - NETBIOS Session Service
    • TCP 445 - Microsoft Directory Services
config 'rule' option 'src' 'lan' option 'proto' 'udp' option 'dest_port' '137-138' option 'target' 'ACCEPT' config 'rule' option 'src' 'lan' option 'proto' 'tcp' option 'dest_port' '139' option 'target' 'ACCEPT' config 'rule' option 'src' 'lan' option 'proto' 'tcp' option 'dest_port' '445' option 'target' 'ACCEPT'

Required Packages

Server (OpenWrt)

  • samba??-server ←- check current available version using opkg list | grep -i samba
  • kmod-fs-???? Kernel module for the file system with which the partition, you want to grant access to with samba, is formated
  • luci-app-samba (optional) Configure from within the web interface LuCI.

Client (your PCs)

Windows and most GNU/Linux distribution come with pre-installed support for this. So does MacOS X since version 10.2. In case your distribution is missing support, you need to install the client software. ArchLinux offers a Wikipage: https://wiki.archlinux.org/index.php/Samba#Configuration.

Configuration

/etc/config/samba After modifying any of the config files, restart samba so that your changes take place:

/etc/init.d/samba restart

Info: When samba is restarted that way, the file /etc/samba/smb.conf is created/recreated conform to the uci configuration file and /etc/samba/smb.conf.template, and the new settings will take effect.

Create samba users by adding them to /etc/passwd and /etc/group then using smbpasswd to set passwords and add to samba. Setup shared directories permissions according to your needs using chown and chmod. Any unknown usernames used for authentication against samba are mapped to a guest login silently by default.

Custom configuration surpassing the UCI configuration

Samba is the only built in way to share resources between computers running Microsoft Windows. Even in a professional environment. Thus it can be very complicated to configure! It is also not the protocol of choice to accomplish that task in a Linux/Mac environment. So, if for whatever reasons above configuration does not give you desired access to your configured shares, you can of course circumvent the uci system and hack the original samba configuration files instead or in addition. There may be entries which do not have a counterpart in UCI (yet) and thus can only be configured that way. Just bear in mind, that the uci config will overwrite the values configured with it (but not the whole configuration) at every boot up! If you want configure samba directly with /etc/samba/smb.conf instead of /etc/config/samba, it is possible to make changes to the smb.conf survive a reboot using the procedure below.

First, prevent OpenWrt from starting samba at boot time, thus overwriting /etc/samba/smb.conf with the settings in the uci file /etc/config/samba:

/etc/init.d/samba disable

Then add the following lines to /etc/rc.local to allow smbd and nmbd to start at boot time, using /etc/samba/smb.conf as the configuration file

smbd -D
nmbd -D

Now edit your /etc/samba/smb.conf all you like without worrying they will be lost the next time you reboot!

Start on Boot

Same procedure as with most OpenWrt packages: The first command will create a symlink /etc/rc.d/S60samba, the second will only start samba right now.

/etc/init.d/samba enable
/etc/init.d/samba start

Troubleshooting

  1. is the partition you want to share mounted correctly? Check →/etc/config/fstab again.
  2. does the samba-daemon have (read or write) access to the partition?
  3. is samba running?
    1. ps aux should show smbd -D and nmbd -D up and running
  4. is your samba configuration right?
  5. does your firewall allow clients to access the service on your router?

While using a Windows 7 client, you may have troubles accessing the network shares when samba is set to user security, especially when using the "Map Network Drive" option from within Explorer. To circumvent this problem, try logging, choose to login using different credentials and type your username all in caps.

If this still doesn't work, on the Windows 7 client(s) start a command shell (Win+R, type cmd and press enter), then issue the following command:

net use R: \\openwrt\<share> /USER:<USERNAME> <password>

If you changed your router hostname, openwrt must be changed accordingly. <share> is the name of the share, as you have configured it using Luci or otherwise. <USERNAME> is the username you have added to the /etc/passwd name, and must be spelled all in caps. <password> is the one you set using smbpasswd.

Set security to share

Some hints in advance: If you installed all needed packages, configured samba per UCI and it still does not work at all, have a look at the file /etc/samba/smb.conf.template. Change the entry security from user to share, restart the daemons and try accessing it directly: In windows explorer type \\router_ip in the address bar. In nautilus or dolphin press <CTRL>+<L> and type smb://router_ip/ into the address bar.

Instead of looking up the whole configuration step by step, you maybe want to have a look at Samba.org: Example Network Configurations. Chapter 1: No-Frills Samba Servers. Notice that you can already achieve a great deal of security by neatly setting up the firewall 8-)

Localhost

If samba does not start, try adding your router's name and ip in /etc/hosts. (see also http://forum.openwrt.org/viewtopic.php?id=5401)

Browsing shares fails

When samba is configured, the shares are set browse-able, but they still don't appear when browsing the network, then it may be that local master = yes is missing from /etc/samba/smb.conf.template. Also check if preferred master = yes is in /etc/samba/smb.conf.template.

Cannot write to the Samba share

If you cannot write to the share, samba may not have the proper permissions to write to the shared folder.

Some have reported success by modifying the permissions and owner of the folder:

chmod -R 777 /mnt/sda1
chown -R nobody /mnt/sda1

If you are sharing a drive mounted wish fstab, you may need to modify /etc/config/fstab to include 'umask=000' in the options section.

config 'mount' option 'options' 'rw,umask=000' option 'enabled_fsck' '0' option 'enabled' '1' option 'device' '/dev/scsi/host0/bus0/target0/lun0/part1' option 'target' '/mnt/usbdisk' option 'fstype' 'vfat'

More info here: https://forum.openwrt.org/viewtopic.php?id=26625

International Characters Support

I've replaced

unix charset = ISO-8859-1

with

unix charset = UTF-8

in the /etc/samba/smb.conf.template file and I can now read and write files and folders with accented characters.

Throughput Issues

Since netfilter will track every connection, if you use MASQUERADING for example, you should disable con-tracking for data connections. The basic idea looks likes this, you must adapt this to your firewall setting.

$IPT -t raw -A OUTPUT -o $IF_LAN -s $IP_LAN -p tcp --sport 139 -j CT --notrack #------------------ don't track SMB
$IPT -t raw -A OUTPUT -o $IF_LAN -s $IP_LAN -p tcp --sport 445 -j CT --notrack #------------------ don't track SMB
$IPT -t raw -A PREROUTING -o $IF_LAN -s $IP_LAN -p tcp --dport 139 -j CT --notrack #------------------ don't track SMB
$IPT -t raw -A PREROUTING -o $IF_LAN -s $IP_LAN -p tcp --dport 445 -j CT --notrack #------------------ don't track SMB

It probably would rather avoid trouble if you do this UCI conform in /etc/config/firewall:

...
config 'rule'
	option '_name' 'Don'\''t track NETBIOS Service'
	option 'src' 'lan'
	option 'src_port' '137-139'
	option 'dest' 'lan'
	option 'target' 'NOTRACK'

config 'rule'
	option '_name' 'Don'\''t track NETBIOS Service'
	option 'src' 'lan'
	option 'dest' 'lan'
	option 'dest_port' '137-139'
	option 'target' 'NOTRACK'

config 'rule'
	option '_name' 'Don'\''t track Windows Filesharing'
	option 'src' 'lan'
	option 'src_port' '445'
	option 'dest' 'lan'
	option 'target' 'NOTRACK'

config 'rule'
	option '_name' 'Don'\''t track Windows Filesharing'
	option 'src' 'lan'
	option 'dest' 'lan'
	option 'dest_port' '445'
	option 'target' 'NOTRACK'

Notes

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doc/howto/cifs.server.txt · Last modified: 2014/05/05 00:14 by westhouse