1. Chapter Ten Networking with UNIX

2. Objectives Describe the origins and history of the UNIX operating system Identify similarities and differences between popular implementations of UNIX Understand why you might choose a UNIX server for a corporate network

3. Objectives Explain and execute basic UNIX commands Install Linux on an Intel-based PC Use Linux to add groups and users and to change file access permissions Explain how UNIX can be internetworked with other network operating systems

4. Brief History of UNIX Bell Labs - System V Original Developer of the Unix Operating System Original Developer of the Unix Operating System Sold copies of the source code for a small fee Sold copies of the source code for a small fee University of California at Berkeley - BSD Made major modifications to the Unix source code including the TCP/IP network subsystem Made major modifications to the Unix source code including the TCP/IP network subsystem Caldera International and Tarantella jointly own the rights to the UNIX source code The Open Group owns the trademark.

5. Common UNIX Features The ability to support multiple, simultaneously logged in users Hierarchical file systems that incorporate demountable volumes Consistent interfaces for input of data to and output of data from hardware devices, files, and running programs The ability to start processes in the background

6. Common UNIX Features Hundreds of subsystems, including dozens of programming languages Program source code portability Windows interfaces that the user can configure, the most popular of which is the X Window system

7. Proprietary UNIX An implementation of UNIX for which the source code is either unavailable or available only by purchasing a licensed copy from Caldera International and Tarantella Sun’s version of UNIX is called Solaris Sun’s version of UNIX is called Solaris IBM’s version of UNIX is called AIX IBM’s version of UNIX is called AIX HP’s version of UNIX is called HP-UX HP’s version of UNIX is called HP-UX

8. Choosing a Proprietary UNIX System Advantages Accountability and support Accountability and support Optimization of hardware and software Optimization of hardware and software Predictability and compatibility Predictability and compatibilityDrawback Customer has no access to the system’s source code and thus cannot create a custom solution Customer has no access to the system’s source code and thus cannot create a custom solution

9. Open Source UNIX Open source software Software developed and packaged by a few individuals and made available to anyone without licensing fees Software developed and packaged by a few individuals and made available to anyone without licensing fees Also called freely distributed software Also called freely distributed software UNIX-like systems in this category include GNU, FreeBSD, and Linux Different implementations of UNIX-like systems are known as flavors (Red Hat, Caldera, etc.) Freely distributable versions of UNIX include a copyright called the General Public License Freely distributable versions of UNIX include a copyright called the General Public License

10. Why Choose UNIX? Is it compatible with existing infrastructure? Will it provide the security required by the network’s resources? Can the technical staff manage it effectively? Will existing applications run smoothly on it?

11. Why Choose UNIX? Will it accommodate future growth (that is, is it scalable)? Does it support additional services the network’s users require? How much does it cost? What type of support can be expected from the vendor?

12. UNIX Server Hardware Base system unit must include: Motherboard with CPU, memory, and I/O control Motherboard with CPU, memory, and I/O control Network interface card (NIC) Network interface card (NIC) Floppy disk drive Floppy disk drive CD-ROM drive CD-ROM drive One or more fixed disks One or more fixed disks

13. Decisions in Choosing Hardware Table 10-1: Typical hardware requirements for a Linux server For more information, visit: www.linuxdoc.org/HOWTO/Hardware-HOWTO/

14. A Closer Look at Linux Linux multiprocessing Supports symmetric multiprocessing (SMP) Supports symmetric multiprocessing (SMP) Linux memory model From its inception, Linux was created to use both physical and virtual memory efficiently From its inception, Linux was created to use both physical and virtual memory efficiently

15. Linux Kernel Kernel As in NetWare, is the core of the system As in NetWare, is the core of the system Also similar to NetWare, it is possible to add or remove functionality by loading and unloading Linux kernel modules Also similar to NetWare, it is possible to add or remove functionality by loading and unloading Linux kernel modules Analogous to NetWare NLMs

16. Linux File and Directory Structure Hierarchical file system Organization of files and directories on a disk partition in which directories may contain files and directories Organization of files and directories on a disk partition in which directories may contain files and directories FIGURE 10-1 Linux file system hierarchy

17. Linux File Services Linux includes support for multiple types of file systems, including: Local file systems Local file systems Remote file systems Remote file systems Its native file system, called ext2 Its native file system, called ext2 Sun Microsystem’s Network File System (NFS) Sun Microsystem’s Network File System (NFS)

18. Linux Internet Services and Linux Processes Linux Internet Services Apache Apache Open source software application that is the leading Internet Web server Linux Processes Another UNIX innovation is the notion of separate, numbered processes Another UNIX innovation is the notion of separate, numbered processes

19. Linux Command Sampler Command interpreter Program that accepts your typing and runs the command Program that accepts your typing and runs the command Also known as a shell Also known as a shell Keeps track of the command history, much like the doskey command in DOS and Windows 2000 Keeps track of the command history, much like the doskey command in DOS and Windows 2000

20. Linux Command Sampler Manual pages Section 1 covers commands typically entered while typing in a command window Section 1 covers commands typically entered while typing in a command window Sections 2 through 5 document the programmer’s interface to the UNIX system Sections 2 through 5 document the programmer’s interface to the UNIX system Section 6 documents some of the amusements and games that are included in the UNIX system Section 6 documents some of the amusements and games that are included in the UNIX system

21. Linux Command Sampler Manual pages Section 7 describes the device drivers for the system Section 7 describes the device drivers for the system Section 8 covers the commands used by administrators to manage the system Section 8 covers the commands used by administrators to manage the system Section 9 documents the UNIX kernel functions programmers use when writing device drivers Section 9 documents the UNIX kernel functions programmers use when writing device drivers

22. Linux Command Sampler Globbing Form of filename substitution Form of filename substitutionPipe Serves as the connection between two commands Serves as the connection between two commandsPipeline Two or more commands separated by a pipe Two or more commands separated by a pipe

23. Linux Command Sampler TABLE 10-2a: Commonly used Linux commands

24. Linux Command Sampler TABLE 10-2b: Commonly used Linux commands (cont.)

25. Linux Command Sampler Linux systems keep quite a bit of information about each file, including: Filename Filename File size (in bytes) File size (in bytes) Date and time a file’s i-node (file information node) was created Date and time a file’s i-node (file information node) was created Date and time that the file was last accessed Date and time that the file was last accessed Date and time that the file contents were last modified Date and time that the file contents were last modified

26. Linux Command Sampler Information Linux system keeps about each file (cont.): Number of “aliases” or links to the file Number of “aliases” or links to the file Numeric identifier of the user who owns the file Numeric identifier of the user who owns the file Numeric identifier of the group to which the file belongs Numeric identifier of the group to which the file belongs Access rights for the owner, the group, and all others Access rights for the owner, the group, and all others

27. Linux Command Sampler To learn about the i-node information, use the ls command Figure 10-2: Example of output from ls

28. Linux Command Sampler Valid file types “d” for directories “d” for directories “l” for symbolic link files “l” for symbolic link files “b” for block devices “b” for block devices “c” for character device files “c” for character device files

29. Linux Command Sampler FIGURE 10-3 Anatomy of ls output

30. Linux Preinstallation Questions What is the new server’s name? What is the server’s IP address? What kind of video card is installed in the server? What kind of monitor is attached to the new server? What is the administrative user’s password? How can I remember all this information?

31. Linux Preinstallation Questions Linux very peacefully coexists with other operating systems on your primary hard drive Read more about multiboot systems at the Linux installation HOWTO site: http://www.linuxhq.com/ldp/howto/Installation- HOWTO/index.html http://www.linuxhq.com/ldp/howto/Installation- HOWTO/index.html

32. The Installation Process Figure 10-4: Welcome to Red Hat Linux screen

33. The Installation Process Figure 10-5: Network Configuration screen

34. Configuring Linux for Network Administration Adding groups and users Groupadd Groupadd Command to add a new group ID to a Linux system Useradd Useradd Command to add a new user ID to a Linux system

35. Changing File Access Permissions Linux restricts access to resources by comparing user and group IDs with the owner and membership of files Every file and directory on a Linux system is owned by exactly one user and is a member of exactly one group You may assign access permissions for the file’s owner, the file’s group, and everyone else

36. Internetworking with Other Network Operating Systems SambaIPX/SPXAppleTalkX3270WINEVMWare Dozens and dozens of command-line utilities that enable access to contents of files generated on other systems

37. Chapter Summary The UNIX system is stable, robust network operating system The key difference between freely distributable UNIX and proprietary implementations is that the copyright on freely distributable implementations require that anyone purchasing an open source version of UNIX receive access code to the source UNIX systems make great Internet servers One characteristic of all UNIX systems is a user- definable command interpreter

38. Chapter Summary The UNIX system was among the first operating systems to include a hierarchical file system Each UNIX process represents an instance of a running executable program in core memory UNIX commands can be likened to ordinary sentences Most UNIX commands are lowercase alphabetic characters

39. Chapter Summary Command names are usually acronyms or abbreviations The system uses information nodes (i- nodes) to store everything other than the actual contents of files Linux distributions are binary compatible UNIX systems quite competently interoperate with other network operating systems