samba server message block file & print server. service profile type: system-v managed service...

SAMBA

Server Message Block File & Print Server

Service Profile

Type: System-V managed service Packages: samba-common, samba-client Daemons: nmbd, smbd Script: smb Ports: 137/udp, 138/udp 139/tcp Configuration: /etc/samba/smb.conf

SaMBa

Client & Server for the Common Internet File System (CIFS) Microsoft's name for its SMB protocol

implementation Contains components of the LanManager

and NetBIOS protocols Samba may provide performance

improvements over ‘native’ CIFS Hhtp://www.samba.org

The goal of SAMBA

A single integrated work-group spanning Windows and Linux machines

The view from Windows

Linux based resources look identical to Windows based resources.

Using Universal Naming conventions (UNC): \\toltec\spirit

The view from Linux

# smbstatusProcessing section "[homes]“Processing section "[printers]“Processing section "[spirit]“

Samba version 2.2.6Service uid gid pid machine spirit jay jay 7735 maya (172.16.1.6) Sun Aug 12 12:17 2005spirit jay jay 7779 aztec (172.16.1.2) Sun Aug 12 12:49 2005jay jay jay 7735 maya (172.16.1.6) Sun Aug 12 12:56 2005

The view from LinuxLocked files:Pid DenyMode R/W Oplock Name-----------------------------------------------------------------------------------------------------7735 DENY_WRITE RDONLY NONE /u/RegClean.exe Sun Aug 12

13:01:22 2005

Share mode memory usage (bytes): 1048368(99%) free + 136(0%) used + 72(0%) overhead = 1048576(100%) total

Samba Services

Authentication & Authorization of users File & Printer Sharing Name Resolution

Provides some capabilities of a WINS serverMaps between NetBIOS names to IP addresses

Note that WINS is independent and unrelated to DNS

Browsing (service announcements)

NetBIOS Names

16 Bytes in length 15 bytes for the selected name

All standard characters a-z, A-Z, 0-9 and ! @ # $ % ^ & ( ) - ' { } . ~ are allowed.

It is normal practise to use the same machine name for the DNS record and the NetBIOS record.

The 16th byte indicates the unique service provided by the machine

Examples of NetBIOS resource types

Named resource Hexadecimal byte valueStandard Workstation Service 00Messenger Service 03RAS Server Service 06Domain Master Browser Service 1B(associated with primary domain controller)Master Browser name 1DNetDDE Service 1FFileserver (including printer server) 20RAS Client Service 21Network Monitor Agent BENetwork Monitor Utility BF

Querying NetBIOS names

C:\>nbtstat -a toltec

NetBIOS Remote Machine Name Table

Name Type Status

---------------------------------------------

TOLTEC <00> UNIQUE Registered



...

Workgroups

SMB groups are the same as Windows Workgroups. There are predefined group resource types.

Nbtstat output:NetBIOS Remote Machine Name Table Name Type Status ---------------------------------------------------------------- METRAN <00> GROUP Registered METRAN <1E> GROUP Registered ..__MSBROWSE__.<01> GROUP Registered

Smb.conf sections

Similar layout to the windows.ini file split into different [ … ] sections

[global]: generic server or global settings which apply to each share

[homes]: used to grant some or all users access to their home directories

[printers]: defines printer resources and services

Sample global section

# Simple global section

[global]

Log file = /var/log/samba/samba.log

Load printers=yes

Max log size=50

Netbios name=RHL

Server string=Samba Server

Workgroup=Tardis

Configuring File and Directory Sharing

Shares should have their own [ … ] section Options include

Public- can be accessed by guest account Browseable – share is visible in browse lists Writeable – resource is read and write enabled Printable – resource is a printer, not a disk Group: all connections to the share use the

specified group as their primary group

Example

# share Ronan’s Home Dir[ronan-home]

Comment= Ronan’s Home DirectoryPath = /home/rbradleyBrowseable=yesWriteable=yesPublic = yescreateMode=0664DirectoryMode=0775maxConnections=1Printable = no

Printing

Printers defined in /etc/cups/printers.conf

Global options as follows: [printers]

path = /var/spool/samba browsable = yes public = yes guest ok = yes writeable = no printable = yes

Printing

[LibertyLane] Comment = Staff Printer LaserJet 5 printer = prll valid users = rbradley smcneally path = /var/spool/prll public = no writeable = no printable = yes

By default, samba assumes printing is via cups, this can be overridden with the printing= parameter in the [global] section

Other examples

[lp] print command = lpr -s -P %p %s; rm %s printable = yes browseable = no

[nec-raw] comment = Main PostScript printer driver for Windows

clients printer driver = NEC SilentWriter 95 printable = yes browseable = yes

Supporting WINS

Turn WINS support on add in [global]: wins support = yes The SaMBa server will maintain a database of

NetBIOS to IP mapping and acts as a name server for these mappings

Specify the name resolution order name resolve order = wins lmhosts bcast

Note that this example shows the the default order and is therefore unnecessary

Name resolution options host means use the system resolver library to

determine the IP address of a name lmhosts means to read name-IP mappings from

the NetBIOS lmhosts file /etc/samba/lmhosts If this doesn’t exist, lmhosts lookup will be skipped

wins tells the server to maintain a WINS database Names will be added and updated as clients connect

bcast uses the NetBIOS broadcast mechanism to find the addresses of all hosts Broadcast storms

Authentication

There are a number of mechanisms for implementing Authentication in Samba

By setting the security= setting this can be controlled by administrators User: Validation is done on a per-user basis, requiring a local

smbpasswd file and also smbusers file Server: Validation done by another server share: Validation on a per-share basis. Will block all public

access domain: a workgroup with a collection of authentication data is

usedworkgroup = NAME

Local file based Authentication

To create the local password file use cat /etc/passwd ¦ mksmbpasswd.sh >

/etc/samba/smbpasswd

Specify that passwords should be stored encrypted encrypted passwords = yes

Specify the servers to be contacted for authentication information (used when security option is not user). password server = host1 host2 host3

Adding users and setting passwords

To add a user smbadduser ronan.bradley:rbradley UNIX Username: Windows Username, need not match

Encrypted (by default) passwords stored in /etc/samba/smbpasswd

Users added with smbadduser and smbpasswd Users defined in /etc/samba/passwd must exist

in /etc/passwd

Passwords

Encrypted passwords stored in /etc/samba/smbpasswd

Users added with smbadduser and smbpasswd Users defined in /etc/samba/passwd must exist

in /etc/passwd To add a user

smbadduser rbradley:rbradley UNIX Username: Windows Username, need not match

Passwords

Use smbpasswd for subsequent password changes for all users

Can also specify valid users in /etc/samba/passwd, but specify that a Primary Domain Controller will manage the passwords

Winbind

winbind maps between windows user and group IDs and unix user and group IDs

COMP+rbradley or STUDENT\srooney6 or COMP\STAFF or STUDENT:FT211-4

Linux Client access with Samba

Smbclient is the standard client utility, useful for testing and for scripts

Smbfs is an optional kernel component which allows Linux to mount an SMB share directly, in similar fashion to mounting an NFS share Not available on UML

Smbclient syntax

If you do not specify username%password, smbclient will use the upper case version of USER or LOGNAME variable and the PASSWORD variable (if set)

If you use the –U option smbclient –U rbradley%letmein Not a great idea, as the command issued is visible in the

history and in the ps information

Smbclient includes an ftp-like shell

Sample smbclient –L output smbclient -L toltecadded interface ip=172.16.1.1 bcast=172.16.1.255 nmask=255.255.255.0Password:Domain=[METRAN] OS=[Unix] Server=[Samba 2.2.5] Sharename Type Comment --------- ------ --------------test Disk For testing only, please IPC$ IPC IPC Service (Samba 2.2.5) HP Printer HP 932C on Maya ADMIN$ Disk IPC Service (Samba 2.2.5)

Server Comment --------- ------- MAYA Windows 98 MIXTEC Samba 2.2.5 TOLTEC Samba 2.2.5 ZAPOTEC Workgroup Master ---------------- -------METRAN TOLTEC

Samba Daemons

Nmbd: NetBIOS name server Supports resource browsing (i.e. identification of

available shares and printers) Provides the WINS server (i.e. maintains the

database of available NetBIOS name to IP mappings)

Smbd: SMB/CIFS server Authentication and authorization File and Printer Sharing

Samba Daemon

When an SMB client starts, it needs to know the IP address being used by a particular host

Client broadcasts this request on the network and receives a response from nmbd containing the NetBIOS information

Configuration Testing

testparm is used to test the correct configuration of your samba settings

To check what access will be granted to a given host, you can also supply the IP address of a given host testparm 147.252.224.78 Will return which resources are accessible to that host

Samba Client

smbclient can be used as a command-line file retrieval/transfer tool smbclient //machine/resource

cd directory get file

Also allows simple view of shared resources smbclient –L hostname

user%password may be specified with the –U option or by setting and exporting USER and PASSWORD environment variables

Samba Client

If you do not specify username%password, smbclient will use the upper case version of USER or LOGNAME variable and the PASSWORD variable (if set)

If you use the –U option smbclient –U rbradley%letmein Not a great idea, as the command issued is visible in the

history and in the ps information

Smbclient includes an ftp-like shell

Sample smbclient –L output smbclient -L toltecadded interface ip=172.16.1.1 bcast=172.16.1.255 nmask=255.255.255.0Password:Domain=[METRAN] OS=[Unix] Server=[Samba 2.2.5] Sharename Type Comment --------- ------ --------------test Disk For testing only, please IPC$ IPC IPC Service (Samba 2.2.5) HP Printer HP 932C on Maya ADMIN$ Disk IPC Service (Samba 2.2.5)

Server Comment --------- ------- MAYA Windows 98 MIXTEC Samba 2.2.5 TOLTEC Samba 2.2.5 ZAPOTEC Workgroup Master ---------------- -------METRAN TOLTEC

nmblookup

Can be used to query a WINS server To list a specific machine

nmblookup –U server –R ‘name’

Or to list all machines nmblookup \*

Queries a WINS server in the same way nslookup (or dig) queries a DNS server

Will return hostname and IP

smbmount

SMB file system can be supported by the LINUX kernel Not available in UML

Can use smbmount to mount a SMB-shared resource smbmount service mountpoint –o options

smbmount //server/resource /mnt/smb –o username=smbuser

Must set CONFIG_SMB-FS set on for smbmount to work

Samba mounts in /etc/fstab

Samba mounts can be performed automatically upon system boot by editing /etc/fstab

Specify the UNC path the local mount point smbfs as the file system and a username

//server1/resource /mnt/smb smbfs deaults,username=nobody 0 0

Samba Resources

http://info.ccone.at/INFO/Samba/introduction.html

samba server message block file & print server. service profile type: system-v managed service...

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