The University of Akron Summit College Business Technology Dept.

1. The University of AkronSummit CollegeBusiness Technology Dept. 2440: 141Web Site Administration Server Management Instructor: Enoch E. Damson

2. Web Administrator's View of Server Management • The Web server software is a product that works with the operating system • The server computer can run more than one software product such as e-mail and FTP • With both a LAN and the Web, access control is very important Server Management

3. Networking Models • Two main approaches to networking includes: • Microsoft LAN approach to networking • Client/server approach to networking Server Management

4. Microsoft LAN Networking Models • Microsoft Windows LAN is configured using one of these two models: • Workgroup • Domain • The model determines how users are organized Server Management

5. Workgroup Networking Model • Treats each computer in the network as an equal, or peer • Also called peer-to-peer networking • Each computer is a client and a server • When you allow others to access resources on your computer, your computer is acting as a server • When you access resources on another computer, your computer is acting as a client • Appropriate for networks with 10 or less computers Server Management

6. Workgroup Networking Model… • Disadvantages: • Most users do not want to administer resources on their computer • Need user names and passwords of users who need resources • Difficult to keep track of changing passwords Server Management

7. Domain Networking Model • One or more servers centralize control • Computers are part of a domain • Single, centralized logon • Single point of control • Users can be given access to resources anywhere in the domain Server Management

8. Client/Server Networking Model • Client represents a program such as a browser or an e-mail client • Server has a corresponding program that communicates with the client • Client and server communicate using a protocol • Web browsers (client) and Web servers use HTTP to communicate • Access to servers controlled by a service/daemon • Networking in Linux follows the client/server model • Each computer has its own database of users/passwords Server Management

9. Server Users • User account – consists of a username and password to identify each user • Usually has a home directory for storing files • User owns any files created in the home directory • Usually a user’s email address (if an email service is provide on the system) • Users can log in and upload files if an FTP server is running on the machine Users & Documents

10. User Accounts • Systems administrators need to maintain user accounts by: • Creating new user accounts • Maintaining the integrity of user accounts • Deleting accounts of users not needing access • Scripts can be used to speed things up when creating many user accounts Users & Documents

11. Creating User Accounts • Creating an account generally involves: • Creating a home directory for a user • Setting permissions and groups • Installing any login scripts or default directories and files for the user • Configuring e-mail if necessary Users & Documents

12. Maintaining User Accounts • With many users, the users’ home directories should all be in a partition or drive separate from the core operating system • Keeps the server running smoothly even if users fill available space on the drive • Users must be given a quota to keep them from taking up too much space Users & Documents

13. Authenticating Users • Authentication – the process of determining a user’s true identity • Process of determining a user's true identity • Three basic methods • What you know – user name and passwords • What you have – entry card • Who you are – biometrics • Windows authentication could be accomplished using: • Kerberos – developed at MIT to allow exchange of private information across a network • Certificates – guarantees the identify of an organization or user Server Management

14. Managing Users and Groups • Users need accounts to access resources on a server • On a Web server there is a restricted account that is used on behalf of Internet users • In a LAN, users with common resource needs are put in a group, and the group is given access to the resource Server Management

15. Managing Users and Groups… • Windows has an account called system • It represents the operating system and it has many of the same privileges of the administrator • Often needed by server programs • Linux typically uses unique accounts for each daemon Server Management

16. Users and Groups in Windows • Local accounts exist on a single computer and can be used to control resources only on that computer • Domain accounts can be used to control resources on all the computers that are part of the domain • Active Directory (AD) allows domains to be grouped into a forest Server Management

17. Groups in Windows • Domain local groups have members from the same domain • Assign permissions to resources in the same domain • Global groups have members from the same domain • Can be used to assign permissions to resources in any domain • Universal groups can have members from any domain • Can be used to assign permissions to resources in any domain Server Management

18. Users and Groups in Linux • Properties of user accounts Server Management

19. File System Permissions • Permission allow you to control access to the resources on a computer such as a Web page, a document, or a program • In Windows, the NTFS file system is required in order to assign permissions • All Linux file systems incorporate permissions Server Management

20. File System Permissions in Windows Server Management

21. File System Permissions in Linux Server Management

22. Linux File Permission Commands • The following commands are used for Linux permissions: • umask – sets the default file/directory permission • chmod – changes the access permissions of a file or directory • chgrp– changes the group associated with a file • chown– changes the owner associated with a file Server Management

23. Linux File Permissions • Permissions are set for three types of users: • User (u) • Group (g) • Others (o) • The three permissions (with their numeric values) are: • Read (r) = 4 • Write (w) = 2 • Execute (x) = 1 • Linux permissions may be set using the chmod command in two ways: • Numeric values • Mnemonics Server Management

24. Mnemonic Characters for Linux File Permissions • Types of users: • a all • u user • g group • o other • Permissions: • d directory • r read (4) • w write (2) • x execute (1) • - none (0) • Actions: • = assigns permission • + adds permission • - removes permission • Use commas to separate assignment units, with no spaces Server Management

25. Linux File Permission ExamplesUsing umask • The umask command uses the numeric values for read (4), write (2) and execute (1) permissions to determine which ones will be unavailable to the category of users (user, group, others) when a file is created • Setting default file permissions for all three categories of users (user, group, others) to have all (read, write and execute) permissions • umask 000 • Setting default file permissions for all three categories of users (user, group, others) to have none of the permissions (read, write and execute) • umask 777 Server Management

26. Setting Linux Default File Permissions Server Management

27. Linux File Permission ExamplesUsingchmod • Assigning read, write and execute permissions to all users on a file: • chmod a=rwx file • chmodugo=rwx file • chmod u=rwx,g=rwx,o=rwx file • chmod 777 file • Assigning read, write permissions to user and execute permission to group and other users on a file: • chmod u=rw,go=x file • chmod 611 file • Adding read, write permissions to all users on a file: • chmodugo+rw file • chmoda+rw • Adding read, write permissions to user and group; and execute permission to other users on a file: • chmodug+rw,o+x file • Removing read, write permissions from all users: • chmod a-rw file • chmodugo-rw file • Removing write permission from group and other users: • chmod go-w file Server Management

28. Setting Linux File Permissions Using Numeric Values http://permissions-calculator.org Server Management

29. Setting Linux File Permissions Using Mnemomics http://permissions-calculator.org Server Management

30. Sharing Resources in a Windows Network • Shared folders require permissions • When comparing share permissions and NTFS permissions, the most restrictive permission takes precedence Server Management

31. Enforcing Network Policies • You can control a number of policies in both Windows and Linux • Windows has many more policies but the majority are appropriate for LANs • A common policy involves passwords • Number of days before change allowed • Number of days before change required Server Management

32. Document Hierarchy • Files and directories on Web servers are organized in a file system. • File system – determines: • Where files are stored on a computer’s hard drive • How many letters a filename can contain • The security of files stored on the computer • There are many different file systems and most modern operating systems can support more than one Users & Documents

33. Common File Systems • Some of the most common file systems are: • FAT32 – Microsoft file system • NTFS – Windows NT file system • UFS – UNIX file system • ext3, ext4 – Linux file system • HFS – Macintosh hierarchical file system • NFS – Network file system Users & Documents