Samba

• Open-source implementation of the SMB protocol used by Microsoft
• Created by Andrew Tridgell in 1992
• He sniffed packets and reverse-engineered the SMB protocol
• Unlike NFS, Samba runs as a user process and is not part of the kernel

• Your Linux/Unix directories can appear on your Windows platform
• typically mapped as a drive letter
• Your Windows directories can be mounted on your Linux/Unix machine

• SMB (Server Message Block): used in Microsoft networking
• also known as CIFS (Common Internet File System)
• implements file and print services, and authentication
• NBT (NetBIOS over TCP) is an extension of NetBIOS
• NetBIOS is the protocol that allows browsing on a Windows network
• implements name resolution, browsing, and service announcement
• nbtd can also emulate a fully-featured WINS server
• translating NetBIOS names and IP addresses
• a browse master for a workgroup, or to take part in master browser election

Setting up a Samba Server

• check to see if the rpm is installed

$ rpm -qa | grep samba
samba-client-x.y.x
samba-x.y.z
samba-common-x.y.z
 
• install these package if they are not on your system

# rpm -ivh samba-x.y.z.rpm

• Save a copy of smb.conf before you begin so you can always get back to square one!
• For simple implementations the smb.conf configuration file will work without any modification
• Configure directories and printers that you want to share and there access rights
• The config file provides templates and comments to help make configuration easier
• See the man page for more info
• man 5 smb.conf

The Global Settings

• workgroup:  Windows workgroup or domain
• server string:  Description field that appears in browse lists
• hosts allow:  For security you should modify the hosts allowed to access shares
 
hosts allow =192.168.1. 127.
hosts allow =.example.com
hosts allow = 192.168.1.0/255.255.255.0
hosta allow = 150.203. EXCEPT 150.203.6.66
• load printers: Set to yes it will share the printers in your /etc/printcap
• security:
• Set to user clients are required to enter a username and password
• Set to share the authentication is on a per share basis
• Set to domain the authentication is done by the PDC
 
security = user
• encrypt passwords: Used by smbclient, Windows NT 4.0, Win95/98, and 2k expect encrypted passwords unless you edit the registry, but that's not a good idea.
• smb passwd file: Provides smbclient the Windows-hashed passwords

Share Settings and Examples

• path: the absolute pathname to the share
• browseable: appear in browse list
• writeable: authorized users can write to the share
• printable: used for printers
• public: user nobody ok to access
• valid users: only needed if not public
[homes]
    comment = Home Directories
    browseable = yes
    writable = yes

[ftp]
    comment = the ftp directory
    path = /var/ftp/pub
    public = yes
    writeable = no
    printable = no

[eng]
    path = /prj/eng
    hosts allow = 192.168.0.128/255.255.255.192
    public = no
    writeable = yes

valid users = tomo rita robert
[printers]
   comment = All Printers
   path = /var/spool/samba
   browseable = no
   # public = yes to allow user 'guest account' to print
   guest ok = no
   writable = no
   # Can write to print spool only
   printable = yes

Check your configuration file!

 
# testparm
Load smb config files from /etc/samba/smb.conf
Processing section "[homes]"
Processing section "[printers]"
    ...

# /etc/rc.d/init.d/smb start
OR
# service smb start

• These are the Windows-hashed passwords used by the smbclient process
• If you specify encrypted passwords, you must supply them!
• The password doesn't have to be the same as the users Windows password

# touch smbpasswd
# smbpasswd -a userxx

Windows users also need an account in /etc/password to access home directories

• A user is logged in as mikek on his Windows machine and wants to see his home directory on the Linux/Unix server.
• He will need to have an account and home directory on the Linux/Unix server
• use the useradd utility to create that account

• edit the /etc/passwd file and the /etc/shadow file, adding the user

   Another possible solution is to map a Windows user account to one of your Unix user account

• edit /etc/samba/smbusers
• add the following line but replace the xy and xx with the appropriate user number
• left of the equal is the Unix account, right of the equal is the Windows account

userxx = 107userxy
 

• make sure that
username map = /etc/samba/smbusers
is uncommented in the /etc/samba/smb.conf file
• Samba will be expecting the password you created for userxx

Troubleshooting Samba

The smbclient command is run on the Linux/Unix machine.

You may need to provide the smb password you just created

The -N should suppress the password prompt

$ smbclient -L stationxx -N

you may need to provide your windows password

The -N should suppress the need to provide a password

$ smbclient -L Windows-stationxx -N
 
• Try connecting to one of your Linux shares
• This command in not unlike ftp where you can ls, put, and get files

$ smbclient //stationxx/homes
added interface ip=10.2.135.212 bcast=10.2.135.255
nmask=255.255.255.0
Password:
Domain=[EXAMPLE] OS=[Unix] Server=[Samba 2.2.3a]

smb: \> ls
...
smb: \> quit

• See which machines are running NetBIOS on your network
• nmblookup is run on the Linux/Unix machine

$ nmblookup '*'
192.168.1.25 *<00>
192.168.1.5 *<00>
192.168.1.6 *<00>
192.168.1.30 *<00>
192.168.1.20 *<00>

• You can turn up the log level in the smb.conf file to help find problems
• Set the log level to 3 to create more logging information


log level = 3
 

• Log files can be found by default in /var/log/samba
• Samba requires the ability to use the LanMan authentication
• Check Local Security Policy, expand Local Policies, click Security Options
• Select LAN Manager Authentication Level
• Set "Send LM & NTLM responses use NTLMv2 security if negotiated"
• Samba requires the LAN Manager password, which is unfortunate

Mapping your Linux share onto your Windows machine

net view \\10.2.135.xx

net use z: \\10.2.135.xx\homes
OR
Go to Windows Tools menu and Map Network Drive

mount your Windows share on your Unix machine

• have a mount point on the Unix machine
• have a share to access on the Windows machine
• The windows machine in this example is named michoacan

# mkdir /mnt/win_share
# mount -t smbfs -o username=pattyo //michoacan/test /mnt/win_share
OR
# smbmount //michoacan/test /mnt/win_share -o username=pattyo
INFO: Debug class all level = 3   (pid 5411 from pid 5411)
opts: username=pattyo
mount.smbfs started (version 2.2.3a)
added interface ip=192.168.1.20 bcast=192.168.1.255 nmask=255.255.255.0
resolve_lmhosts: Attempting lmhosts lookup for name michoacan<0x20>
resolve_hosts: Attempting host lookup for name michoacan<0x20>
Connecting to 192.168.1.25 at port 139
Password:
 
• If you use this command without the username option, you will need to provide the Administrator password
• Note the smbfs file system type, this is either built into the kernel or you will see the kernel module
 
$ lsmod | grep smb
smbfs       36896   1 (autoclean)

$ df /mnt/win_share
Filesystem     1k-blocks  Used     Available Use% Mounted on
//oaxaca/test  6285056    3857024  2428032   62%  /mnt/win_share