Transcript 9781111543709 _PPT_ch11

Guide to Parallel Operating
Systems with
Windows 7 and Linux
Chapter 11
Networking
Objectives
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Explain networking terminology
View TCP/IP settings
Access network resources
View folder and file sharing permissions
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Networking Terminology
• Client/Server Networks
– Client/server model:
• Central idea of networking
• Relationship between two computers
– Desktop computer (the client) makes service
request of another computer (the server)
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Figure 11-1 Client/server relationship
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Peer-to-Peer Networks
• Employ desktop computers that are equally
capable of being both clients and servers
• Example: small office/home office network
• Fedora 13:
– Provides peer-to-peer networking with Samba
– Samba:
• Based on Server Message Block (SMB)
• Identical to protocols provided by Windows 7
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Figure 11-2 Peer-to-peer network
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Networking Terminology (continued)
• LANs (local area networks)
– Usually confined to a geographic area
– Can be small, linking two or three computers
– Often link hundreds of computers used by many
people
• WANs (wide area networks)
– Connects different LANs using services such as:
• Dedicated, leased data lines, satellite links, and data
packet carrier services
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Figure 11-3 Local area network
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Figure 11-4 Wide area network
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Networking Terminology (continued)
• Internet
– System of linked networks
– Communications highway for millions of users
• Intranet
– Private network that uses Internet-type applications
– Available only within a single organization
– For large organizations:
• Allows easy access to Web-based applications
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Networking Terminology (continued)
• VPN (virtual private network)
– Uses tunneling to transfer data securely
– Helps to save money by using:
• Public Internet to connect securely with private
network
• Internet Protocol
– Main networking protocol
– Allows communication of data across a network
– Computers can deliver packets based on unique IP
addresses
– Foundation of the Internet Protocol Suite
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Networking Terminology (continued)
• Protocols
– Set of rules that enables two computers to talk to
each other
– Computing standard that defines the syntax and
regulations of a connection across a network
• Internet Protocol addresses
– Identify two computers or devices in a network
– IPv4 (IP Address Version 4):
• 32 bits divided into four octets between 0 – 255
– IPv6: consists of 128 bits
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The Internet Protocol Suite
• Set of protocols used in combination for different
networking tasks
• IP and TCP:
– Underlying standards that all other protocols use
– Commonly referred to as TCP/IP
• TCP:
– Organizes data into packets and sends them to IP
– Rebuilds files from individual packets IP sent
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The Internet Protocol Suite (continued)
• Layers of the Internet Protocol Suite
– Network (or Network Access) layer: links computers
– Internet layer: allows IP to transfer packets across
the link
– Transport layer: uses TCP to organize packets
– Application layer: consists of protocols for specific
types of transfer
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The Internet Protocol Suite (continued)
Figure 11-5 Internet Protocol Suite
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The Internet Protocol Suite (continued)
• Application layer protocols
– HTTP (Hypertext Transfer Protocol): allows Web
users to request Web sites from remote servers
– FTP (File Transfer Protocol): allows for the rapid
transfer of files across the Web
– POP3 (Post Office Protocol 3): sends and receives
e-mail
– SMTP (Simple Mail Transfer Protocol): sends and
receives e-mail
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Viewing TCP/IP Settings
• IP address:
– Numerical label assigned to devices participating in a
computer network
• The subnetwork, or subnet:
– Logically visible, distinctly addressed part of a single
IP network
• The gateway IP address: node on a TCP/IP network
• DNS IP address of server providing domain name
resolution:
– Translates domain names into numerical (binary)
identifiers
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Viewing TCP/IP Settings (continued)
• Dynamic Host Configuration Protocol (DHCP):
– Used by hosts (DHCP clients) to retrieve IP address
assignments and other configuration information
– Uses a client/server architecture
• In the absence of DHCP:
– All hosts on a network must be manually configured
with static IP addresses
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Viewing TCP/IP Settings in Windows 7
• Use Windows 7 GUI tools or command line
• To display the Network Connection Details window:
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Click Start
Right-click Network
Click Properties
Click the Local Area Connection link
Click Details
• No value for the DHCP enabled property indicates:
– An administrator assigned a static configuration
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Figure 11-6 Network
Connection Details window
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Technology/Cengage Learning
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Viewing TCP/IP Settings in Windows 7
(continued)
• IPCONFIG /ALL command:
– Provides network connection details
– To access this information:
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Click Start
Point to All Programs
Click Accessories
Click Command Prompt
Type IPCONFIG /ALL
Press Enter
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Figure 11-7 Network connection details
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Viewing TCP/IP Parameters in Fedora
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• Use GUI tools or Terminal window
• To display Ethernet Device settings:
– Click System, point to Administration, click Network
type your password, and then click Edit, or
– Use the nm-tool command in a Terminal window,
or
– Use ifconfig –a command
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Figure 11-8 Ethernet Device
settings
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Figure 11-9 Network Manager tool
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Accessing Network Resources
• Accessing network resources in Windows 7
– Workgroup:
• Provides a basis for file and printer sharing
• Automatically created when peer-to-peer network is
created
• Default: WORKGROUP
– Homegroup:
• Makes it easy to share libraries and printers
• Protected with a password
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Accessing Network Resources
(continued)
• Network option on the Start menu:
– Displays shortcuts to shared computers, printers,
and other resources on the network
• To open the Network window:
– Click Start and then click Network
• To see shares another computer is offering:
– Type \\servername\ in Windows Search text box
– Click server name
• To see the shares another computer is offering:
– Type NET VIEW \\servername
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Figure 11-10 Network resources shown in workgroup
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Figure 11-11 Shares on the Host01 computer
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Figure 11-12 The NET VIEW command shows shares on the other computer
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Accessing Network Resources
(continued)
• UNC notation use:
– Requires that you know name or IP address of
server and share
• To open a folder to a network location:
– Type the UNC in the search text box
• To access the files:
– Click UNC displayed in the search results text box
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Figure 11-13 Accessing a
network share from the
Search window
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Accessing Network Resources
(continued)
• To access a network share from command prompt:
– Double-click the command Prompt icon
– Type: NET USE [drive letter | *]
\\computer name\share name
– You may specify a drive letter or permit Windows 7 to
provide one:
• Example: NET USE N: \\Windows7\History
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Accessing Network Resources in
Fedora 13
• To access a share, you must mount the share
• After you create a directory for mount destination:
– Type mount command
– Specify UNC for share, logon credentials, and
destination directory
– Once share completes:
• Change directory to mount destination
• Issue an ls command to view the files
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Figure 11-14 Mounting a Windows share in Linux
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Accessing Network Printers
• It makes good economic sense to:
– Share a printer
– Make it available to several users on a network
• Network administrators:
– Responsible for setting up shared printers on the
network
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Folder and File Sharing Permissions
• Managing Windows NT File System permissions
– You must be able to view folder and file permissions
– Only authorized users can access local and network
folders and files
• NT File System required
– To share folders and files with other network users
– Only NTFS:
• Permits user accounts and user groups to be linked to
folder and file permissions
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Managing Windows NT File System
Permissions (continued)
• Using local user groups
– Used to simplify management and authorization of
network resource
– Groups are created to:
• Define sets of user accounts that require access to the
same resources
• Viewing shared folder permissions
– When sharing folder with network users, administrators:
• Must specify the level of access
• Balance security with functionality
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Managing Windows NT File System
Permissions (continued)
Table 11-1 Windows 7 shared folder permissions
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Managing Windows NT File System
Permissions (continued)
• Assigning NTFS permissions
– Administrators secure folders and files on an NTFS
volume
– NT file system is required to use NTFS permissions
– Assign file permissions to control access to files
• Multiple NTFS permissions
– More effective to assign permissions to user groups
– Permissions assigned at file level override those
assigned at folder level
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Managing Windows NT File System
Permissions (continued)
Table 11-2 NTFS folder permissions
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Managing Windows NT File System
Permissions (continued)
Table 11-3 NTFS file permissions
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Managing Windows NT File System
Permissions (continued)
• Permission inheritance
– Inheriting permissions of parent folder by default
– Options to prevent inheritance:
• Copy inherited permissions from parent folder
• Remove inherited permissions and retain only
assigned permissions
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Figure 11-16 Permission
inheritance
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Combining Shared Folder and NTFS
Permissions
• Administrators gain the highest level of security
and control
• NTFS:
– Offers most flexible level of control
– Can be assigned to resources on an individual basis
• To determine effective permissions for a given
network resource:
– Combine shared folder permissions
– Combine NTFS folder permissions
– Determine which permission is the most restrictive
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Figure 11-17 The result of combining shared folder and NTFS permissions
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Moving and Copying Files in NTFS
Volumes
• Files/folders inherit permissions from the
destination folder
• When files/folders are moved within NTFS partition:
– They do not need to be re-created
• When you move a file/folder between NTFS
volumes:
– It must be created on the destination volume
• FAT16 and FAT32 file systems
– Do not supports NTFS permissions
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Viewing Fedora 13 File Permissions
• Each file and directory:
– Has permissions for owner, group, and everyone else
• Permissions for each group:
– Consist of three (binary) bits
• 10th bit is the sticky bit
• To show the file permissions:
– Use the ls command with the –l option
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Viewing Fedora 13 File Permissions
(continued)
Figure 11-19 File permissions in Fedora 13
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Viewing Fedora 13 File Permissions
(continued)
Figure 11-20 Viewing file permissions in Fedora 13
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Figure 11-21 Listing file permissions in Fedora 13
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Viewing Fedora 13 File Permissions
(continued)
Figure 11-22 Displaying file permissions in Fedora 13
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The User Identification Attribute
• File permissions bits:
– Include an execute permission bit for the file owner,
the group, and others
• When the execute bit is set for the owner:
– The SUID bit (set user ID) is set to s
• Permission allows user/process that runs the file to
have same access to system resources as owner
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The Sticky Bit
• Ensures that:
– Only owner who created a file in directory can
delete file and prevent malicious/accidental deletion
• When sticky bit is set:
– A t appears as the third character of the Others
permission bits
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Summary
• Network :
– Computers interconnected by communication paths
• To enable communications in a routed network:
– Computer must have an IP address, subnet mask,
gateway IP address, and DNS IP address
• Network resources, folders, files, and printers are
shared on the network
• File permissions:
– Enable users to access needed files
– Enable groups to share project files and folders
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