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Resource Sharing Over a Network
Guide to Operating Systems Third Edition
Guide to Operating Systems, Third Edition 2
Objectives
After reading this chapter and completing
the exercises you will be able to:
• Explain the principles behind sharing disks and
files on a network
• Set up accounts, groups, security, and disk and
file sharing on network server operating systems
Guide to Operating Systems, Third Edition 3
Objectives (continued)
After reading this chapter and completing the exercises you will be able to:
• Set up disk and file sharing on client operating systems
• Set up printer sharing on server and client operating systems
• Discuss how network and Internet servers are used for vast information-sharing networks
Guide to Operating Systems, Third Edition 4
• One of the first reasons for linking a workstation’s operating system onto a network
• NetWare was early on the scene to enable file sharing through a server
– by downloading a file from a file server
– by purchasing third-party software to create a special shared drive
Sharing Disks, Files and Printers
Guide to Operating Systems, Third Edition 5
• Share entire applications over the network
– Download the entire executable
– Only one version needed on the server
• Mapping
– enables a client workstation to attach to the shared drive of another workstation or server
– drive letter assigned
Sharing Disks, Files and Printers (continued)
Guide to Operating Systems, Third Edition 6
Sharing Disks, Files and Printers (continued)
• Mounted volume
– term used in UNIX/Linux and Mac OS X for a mapped drive
Guide to Operating Systems, Third Edition 7
Securing Shared Resources
• Potential security risk for non-authorized users
to access a file or use a printer
• Operating systems discussed in this book offer
security measures
Guide to Operating Systems, Third Edition 8
Sharing Disks and Files Through Server Network
Operating Systems• Examples of server network operating systems
that share disks and files over a network – Windows 2000 Server
– Windows Server 2003
– UNIX/Linux
– Mac OS X Server
– NetWare
Guide to Operating Systems, Third Edition 9
Sharing Disks and Files Through Server Network
Operating Systems• Network administrator may establish security
– by assigning accounts, account passwords, groups, and access privileges
Guide to Operating Systems, Third Edition 10
Windows 2000 Server and Windows Server 2003
• Uses accounts, groups, and permissions
• Steps involved include setting up the following:
– Groups – Account policies
– User accounts – Permissions
– Shared disk and folders
Guide to Operating Systems, Third Edition 11
Windows 2000 Server and Windows Server 2003
(continued)
• Use groups to manage resources and permissions– Local
– Domain local
– Global
– Universal
Guide to Operating Systems, Third Edition 12
Windows 2000 Server and Windows Server 2003
(continued)
• Groups are defined as security or distribution groups
• Security groups
– used to enable access to resources on a standalone server or in Active Directory
• Distribution groups
– used for e-mail or telephone
Guide to Operating Systems, Third Edition 13
Windows 2000 Server and Windows Server 2003
(continued)• Container object
– entity that is used to group together resources in a directory service
• Tree
– consists of one or more domains
• Forest
– houses one or more trees
Guide to Operating Systems, Third Edition 14
Windows 2000 Server and Windows Server 2003
(continued)• Universal group guidelines
– use global groups to hold user accounts as members
– use domain local groups to provide access to resources in a specific domain
– use universal groups to provide extensive access to resources
– manage user accounts access
Guide to Operating Systems, Third Edition 15
Windows NT Server
• Trusted domain
– such as college.edu
– granted access to the resources in another domain such as research.college.edu
• Trusting domain
– research.college.edu allows access to its resources to college.edu
Guide to Operating Systems, Third Edition 16
Windows 2000 Server and Windows Server 2003
(continued)
• Before any accounts are created, it is wise to establish the account policies
• Three categories:– Password security
– Account Lockout
– Kerberos security
Guide to Operating Systems, Third Edition 17
Windows 2000 Server and Windows Server 2003
(continued)• Password security options:
– enforce password history
– maximum password age
– minimum password age
– minimum password length
– password complexity requirements
– password storage using reversible encryption
Guide to Operating Systems, Third Edition 18
Windows 2000 Server and Windows Server 2003
(continued)• Account lockout options:
– account lockout duration
– account lockout threshold
– reset account lockout count
Guide to Operating Systems, Third Edition 19
Windows 2000 Server and Windows Server 2003
(continued)
• Kerberos options:– enforce user logon restrictions
– maximum lifetime for a service ticket
– maximum lifetime for a user ticket
– maximum lifetime for a user ticket renewal
– maximum tolerance for a computer clock synchronization
Guide to Operating Systems, Third Edition 20
Windows 2000 Server and Windows Server 2003
(continued)
• Share
– an object given a name and made visible to network users
• Disk or folder - shared through its properties
Guide to Operating Systems, Third Edition 21
Windows 2000 Server and Windows Server 2003 (continued)
• Share permissions:– Read
– Change
– Full Control
Guide to Operating Systems, Third Edition 22
Windows 2000 Server and Windows Server 2003 (continued)
• Dialog box in Figure 9-6 has a caching button
• Caching
– enables you to set up a folder so that it can be accessed by a client, even when the client is not connected to the network
• Web sharing
– files available on a Web server for HTML or FTP access
– See Tables 9-2 and 9-3
Guide to Operating Systems, Third Edition 23
Windows 2000 Server and Windows Server 2003 (continued)
Guide to Operating Systems, Third Edition 24
Windows 2000 Server and Windows Server 2003
(continued)
Guide to Operating Systems, Third Edition 25
Windows 2000 Server and Windows Server 2003 (continued)
• Troubleshooting a security conflict:– review folder and share permissions
– take into account what happens when a folder or files are copied or moved
– inherited properties
Guide to Operating Systems, Third Edition 26
UNIX and Linux
• User identification number (UID)– each user account in UNIX is associated with a UID
• Group identification number (GID)– users who have common access needs
Guide to Operating Systems, Third Edition 27
UNIX and Linux (continued)
• The password file (/etc/passwd) contains :– user name
– encrypted password or a reference to the shadow file
– UID
– GID
– information about the user
– location of the user’s home directory
– which shell to use
Guide to Operating Systems, Third Edition 28
UNIX and Linux (continued)
• Shadow file (/etc/shadow) contains password restriction information :– minimum and the maximum number of days
between password changes
– Information on when last changed
– Warning information about password expiration
– Amount of time that the account can be inactive before access is prohibited
Guide to Operating Systems, Third Edition 29
UNIX and Linux (continued)
• Home directories
– areas on the server in which users store data
• Information about groups is typically stored in the /etc/group file
Guide to Operating Systems, Third Edition 30
UNIX and Linux (continued)
• Permissions are granted on the basis of
– ownership
– group membership
– other (or World)
– all (all is not used in every version of UNIX, but is included in Red Hat Enterprise Linux)
• Permissions are set up by using the chmod command
• Chmod has two different formats, symbolic and octal
Guide to Operating Systems, Third Edition 31
NetWare• Novell NetWare server installation
– first task is to design a file structure
• Default directories:– SYSTEM
– PUBLIC
– LOGIN
– HOME
– APPS
– DATA
Guide to Operating Systems, Third Edition 32
NetWare (continued)
• Net Administrator tasks:
– Set security on each directory, subdirectory, and on particular files
– Create an account and account password for each user
– Set up groups as a way to provide shortcuts for managing security
Guide to Operating Systems, Third Edition 33
NetWare (continued)
• Search drive
– given drive letters such as S1 for the first drive, S2 for the second drive, and so on
• Difference between a mapped network drive and a mapped search drive
– NetWare can execute a file on a search drive, whether the file is in the main directory or in a subdirectory under the search drive
Guide to Operating Systems, Third Edition 34
NetWare (continued)
• A login script is a file of commands associated with an account or a group of accounts
Guide to Operating Systems, Third Edition 35
NetWare (continued)
• A user account can be set up in ConsoleOne using several kinds of restrictions:
– Requiring a password
– Setting a minimum password length
– Requiring that a password is changed within a specified interval of time
– The remainder are listed on page 453 of the textbook
Guide to Operating Systems, Third Edition 36
NetWare (continued)• Administrator can grant rights to access
specific directories, subdirectories, and files
• The rights control the ability to:– Perform a directory listing
– Create a new directory, subdirectory, or file
– Read contents of a directory, subdirectory, or file
– Write to the contents of a file
– Refer to the list on page 454 of the textbook for the rest
Guide to Operating Systems, Third Edition 37
NetWare (continued)
• Objects – such as user accounts, groups, printers, directories,
subdirectories, files, and other resources
• Novell Directory Services (NDS)
– stores information about objects
• Leaf objects
– store information about clients
Guide to Operating Systems, Third Edition 38
Mac OS X Server• The Mac OS X Server is designed as a true server
– file sharing
– printer sharing
– managing network users and groups
– providing Web services
• Mac OS X Server
– can support up to several thousand users
– includes the Apache Web server software
– supports TCP/IP and AppleTalk
Guide to Operating Systems, Third Edition 39
Mac OS X Server (continued)
• Included tools
– Server Admin
– Macintosh Manager
• Share points
– shared resources on a server
Guide to Operating Systems, Third Edition 40
Mac OS X Server (continued)
• Logging of events can include:
– Login and Logout events
– Opened files
– Newly created files
– Newly created folders
– Deleted files and folders
Guide to Operating Systems, Third Edition 41
Accessing and Sharing Disks and Files Through Client
Network Operating Systems
• Many operating systems
– include the ability to act as clients
– to map to disks and directories on servers
Guide to Operating Systems, Third Edition 42
• Windows 2000 Professional
– Access a shared drive over the network
– Map the drive using My Network Places
• The steps for mapping a drive are shown on page 457
• Same process for Windows 2000 Server
Accessing and Sharing Resources in Windows 2000 Professional
Guide to Operating Systems, Third Edition 43
Accessing and Sharing Resources in Windows XP
• Uses My Network Places to locate and map network drives
• Fastest way to access My Network Places is to use the steps on page 458
Guide to Operating Systems, Third Edition 44
Accessing and Sharing Resources in Windows XP
(continued)
Guide to Operating Systems, Third Edition 45
Accessing Shared Resources via UNIX/Linux and Specialized
Utilities• Network File System (NFS)
– provides file transfer capabilities
• NFS in Red Hat Enterprise Linux 3.0
– enable portmap
– enable rpc.mountd
– enable rpc.nfsd
Guide to Operating Systems, Third Edition 46
Accessing Shared Resources via UNIX/Linux and Specialized
Utilities (continued)
• UNIX/Linux can access share Windows 2000/XP/Server 2003 with Samba
Guide to Operating Systems, Third Edition 47
Accessing and Sharing Resources via Mac
OS X• In Mac OS X, you connect to another computer that is sharing a
disk or folder by using the Go menu
• To mount a shared drive
– open the Go menu
– select Connect To
Server
– enter address of
server
Guide to Operating Systems, Third Edition 48
Accessing and Sharing Resources via Mac OS X
(continued)
• Establish the network identity and turn on file sharing through System Preferences
• Privileges are set in order to enable access
Guide to Operating Systems, Third Edition 49
Sharing Printing Devices
• Operating systems discussed in this
book have the ability to share printers as
well as disks, directories, and files
Guide to Operating Systems, Third Edition 50
Windows-based Systems
• Configure printing by using the Add Printer Wizard
• Once a printer is set up, it appears in the Printers folder
• In Windows XP and Windows Server 2003, click Start, and click Printers and Faxes
• Right-click the printer to access menu options
Guide to Operating Systems, Third Edition 51
Windows-based Systems (continued)
• Windows 2000/XP/Server 2003 share permissions:– Print
– Manage Documents
– Manage Printers
– Special permissions
Guide to Operating Systems, Third Edition 52
UNIX/Linux
• UNIX printing– log on to the UNIX server and printing to one of its
printers
– set up to use the BSD or the SVR4 spooling system as describe in Chapter 5
• Red Hat Enterprise Linux 3.0– GNOME Print Manager tool
Guide to Operating Systems, Third Edition 53
NetWare
• Shared printing
– queue-based printing
– Novell Distributed Print Services (NDPS)
Guide to Operating Systems, Third Edition 54
Mac OS X
• Methods of printer sharing
– can make a connected local printer available to other computers running the Mac OS on a network
– can attach to a shared printer offered by another workstation on the network
Guide to Operating Systems, Third Edition 55
Network and Internet Resource Servers
• Resource Servers
– NetWare
– UNIX/Linux
– Windows 2000/Server 2003
– Mac OS X servers
Guide to Operating Systems, Third Edition 56
Network and Internet Resource Servers
• Functions
– e-commerce
– video-conferencing
– multimedia
– client/server applications
– web servers
Guide to Operating Systems, Third Edition 57
Summary
• Resource sharing is why networks exist and are thriving
• Security is important for network resources
• Groups, user accounts, and permissions permit or restrict access as determined by the administrator
Guide to Operating Systems, Third Edition 58
Summary (continued)
• Client operating systems have utilities to
enable access or share resources over the
network
• Network server operating systems continue to
provide more and more ways to share
resources