CMPT 471 Networking II

1. CMPT 471Networking II Course Information

2. CMPT 471: Networking II • Monday, Wednesday, Friday 9:30 • Textbook: • Internetworking with TCP/IP Vol. 1: Principles, Protocols, and Architecture (5/e) • Douglas Comer, Prentice-Hall, 2006 • Additional References: • Internetworking with TCP/IP Vol. II: Design, Implementation, and Internals (3/e) • Douglas Comer, Prentice-Hall, 1999: • Routing in the Internet (2/e) • Christian Huitema, Prentice Hall PTR, 2000: • Excellent book on Internet routing protocols.

3. CMPT 471: Networking II • Additional References: • Unix Network Programming, the sockets networking API v1 3rd edition • Stevens, Fenner, and Rudoff, Addison Wesly, 2004 • Building Internet Firewalls (2/e) • Zwicky, E. Cooper, S., Chapman, D., O'Reilly & Associates, 2000 • IPv6 The New Internet Protocol (2/e) • Huitema, C., Prentice Hall PTR, 1998 • The DHCP Handbook 2nd edition • Droms and Lemon, Sams, 2002 • Unix Power Tools 3rd edition • Powers, Peek, O'Reilly and Loukides, O'Reilly, 2002 .

4. Class web-site • All the information discussed today and more can always be found on the class web-site • To find the class web site go to http://www.cs.sfu.ca/CourseCentral/471/jregan • Course Central is also a useful link to abundant information useful to students taking a computing science course

5. Communications

6. CMPT 471 Website

7. My availability

10. Evaluation • Assignments: 35% • Quizzes 25% • Final Examination: 40%

11. Assignments • Five assignments • Each assignment is worth 7% of your course grade • Assignments 1 is to be completed individually • Assignments 2, 3, 4 and 5 may be completed in pairs • Problems similar to the assignments will appear on the midterm and the final. • Help is available by email, during office hours • Complete solutions will be posted for most assignments • Only a selection of problems will be graded

12. Final • One 3 hour final examination • 30%-40% short answer problems • 60%-70% longer problems that utilize several important concepts and require integration of those concepts. • A sample exam, including solutions, will be posted two weeks before the final exam

13. Quizzes • Examples quiz problems from previous semesters with detailed solutions are already posted on the class website • Quizzes and solutions will also be posted to help you review and keep up. • Each quiz is expected to take about 20-30 minutes to answer. • Answers should consist of a short concise paragraph of 30 sentences, about 1 page, explaining a concept or method, or solving the problem. • Keep in mind that most posted solutions are more extensive than expected quiz answers.

15. Important Dates

16. Important Dates

17. Assignments • At least two weeks before the due date the assignment will be posted on the website • Assignments 1 must be completed individually • Assignments 2, 3, 4 and 5 may be completed individually or in pairs • Assignments will be lab exercises illustrating the operation of protocols and problems on material covered in class • Complete solutions to all assignments will be posted • Information of proper preparation of assignments and lab problems is available on the class website.

18. Grading Information • Assignments should be: • submitted electronically using the course management system • Bonus points (10%) are available for submitting assignments more than 48 hours early • No late assignments will be accepted • Unofficial grades will be available in the course management system

20. Readings and Notes

21. Academic Honesty

22. Academic Honesty Read the policy

23. Getting Started: 1 • You will be required to complete many parts of your assignments using the CSIL networking laboratory • A virtual networking laboratory is now available and is accessible remotely (from Windows and Linux machines) • You will have root access on most of the virtual machines of the networking lab (except routers) • You will be running tasks that should not be run (except by a network administrator) outside the networking lab

24. Operating System • In the CSIL labs you will be using computers that run the LINUX operating system • Prepare for your first assignment • In the first week of class familiarize yourself with • Linux and writing simple scripts. • You will receive instructions on how to use the virtual networking lab next week, after this you can familiarize yourself with • Using ethereal the packet capture software • Accessing and using the virtual lab

25. CMPT 471Networking II Linux Primer Getting Ready to use the Network Lab

26. Shell Scripts • Ashell script is an executable file containing a series of shell commands. When the shell script is executed the commands in the file are executed in sequence by the shell. • A shell script records a series of command line actions and easily executes them again and again • Assures repeatability of experiments and processes • Allows long series of commands to be easily tested and debugged • There are different shell scripting languages such as • csh (C shell), tcsh • sh (Bourne shell),bash(Bourne again shell) • Perl ……

27. Selecting a Shell Script Language • On the command line type • the name of the shell followed by return to enter the shell. • exit followed by return to leave the shell. • To determine which default shell you are presently using • echo $SHELL • finger youruserid (your default shell) • The present shell will be indicated by the prompt • To indicate which shell to use inside a shell script • in the first line of your script file #! /bin/csh • To indicate which shell to use when executing a shell script called scriptname • bash scriptname argumentsor csh scriptname arguments

28. Executing a Shell Script • Your script file must be executable, you will need to change the permissions to make it executable (discuss how later in this lecture) • Executing a shell script called scriptname • bash scriptname arguments • csh scriptname arguments • source scriptname arguments • ./scriptname arguments

29. Using Variables in a script • You can define and use your own variables within a shell script. • VariableName=23 (no spaces around =) • Sets the value of VariableName to 23 • echo $VariableName • Echo’s (prints the value of VariableName) to the output line. • VariableName2=$VariableName • Sets the value of VariableName2 to be the value of VariableName1

30. Printing from a Shell Script • To print to the standard output either use echo or run a shell command that produces output • echo “This is a string” • prints the string in the brackets • echo $variablename (also used on command line ) • prints the value of the variable with name variablename • echo “The value of variablename is; $variablename” • Prints the string ‘The value of variablename is; ” followed by the value of variablename • ls • Prints a list of all files in the present directory

31. Command Line Arguments • Passing command line variables into a shell • source scriptname argument1 … argumentn • Inside the script the command line argument values will each have a descriptor, the first argument’s value will be $0, the second argument’s value will be $1 and so on. • The descriptors can be used to represent the command line variables within the script • echo `Second command line variable: $1` • Prints the string “Second command line variable: “ followed by the value of the second command line variable

32. Using Basic Unix Commands • Any basic Unix command can be run from the command line, or from within a shell script • To work with shell scripts you must first be familiar with basic Unix commands • Commands are used to move around within the file system, to create and operate on files, to interact with the operating system

33. Some basic commands • Remember UNIX is case sensitive • yppasswd username (username is optional) • Executed from your command line • Will ask you to input your old password and your new passwd twice • You can only change your own passwd unless you are root • man commandname or info commandname • Tell me how to use the command with name commandname • su • Become the root user (superuser, substitute user) • You will need to be root to complete many of your assignments. Do so with care.. • whoami Tell me my username

34. Directories • Directory creation, navigation, removal • mkdir directoryname make directory directoryname • rmdir directoryname remove empty directory • cd directorypath go to directory directorypath • ls directorypath list files in directory directorypath • cd return to your home directory • ls list files in this directory • pwd show path to and name of current directory • cd .. Move to the parent directory of this directory (one layer further up the directory tree

35. In myhome cd Dir2 (goes to Dir2 ) cd Dir2/Dir5(goes to Dir5 ) In Dir5 cd .. (goes to Dir3) cd ../.. Or cd (goes to myhome) cd ../Dir6 (goes to Dir6) Anywhere cd will take you to myhome (your home directory) cd / takes you to the root directory myhome Dir1 Dir2 Dir3 Dir4 Dir5 Dir6 Dir7 Directory structure

36. Root file structure

37. Files • To make a file open it using your favorite text editor • mv filepath1 filepath2 • Moves (renames) a file or directory • mv a b file previously named a is now named b • mv a ../a file a is moved from the present directory to the parent directory of the present directory • rm filepath removes (deletes) a file • rm a deletes file a from the current directory • rm ../a removes file a from the parent of the present directory • grep pattern filepaths • Find all occurrences of pattern in requested files

38. Files • more filename or less filename • Displays contents of file filename one page (screen) at a time • cp filename1 filename2 • Make a copy of filename1 with name filename2 • cat filename1 filename2 filename3 • Will print the contents of each file in sequence • Contents of filename1 • Contents of filename2 • Contents of filename3

39. Wildcards • Wildcards are used to represent multiple possibilities • * matches any number of characters • ? Matches a single character • Examples • ls a? • List all files in the current directory beginning with a and having a name of length 2 characters. • grep mystring */*file • Find all occurences of the string “mystring” in all files whose names end with the string “file”. The files ending with string “file” must be in a subdirectory of the present directory • rm [a-c]* • Remove all files with filenames beginning with a b or c from the current directory

40. Redirection • Redirect input and/or output • > filename redirect standard output from screen to file. • cat file1 file2 file3 > f4 • A new file f4 is opened and the contents of file1, file2 and file 3 are successively added to the file f4. If f4 exists it will be overwritten. • < filename take input from file filename • a.out < datafile • (a.out is the default output file for a compiled executable) • >> filename redirect standard output from screen to file. Appends output to an existing file • cat file1 file2 file3 >> f4 • The contents of file1 then file2 then file3 will be successively appended to the current contents of f4

41. Piping • Piping allows you to send the output of one process to become the input of another process without using io to store it in an intermediate file • ls a* | more • List the files in the current directory whose names start with a, one page at a time

42. File Permissions • Can usels –l to find present permission for files • drwxrwxrwx for directory • -rwxrwxrwx for file u g o • 3 sets of permissions • User (u) group (g) other(o) • Each set allows or disallows read write & or execute • rwx (allow all) • rw- (read write allowed) • r - - (read only) • Order of sets is ugo

43. Setting File Permissions: 1 • Permissions can be reset by using chmod • chmod can specify permission in two ways • Numeric values read(4) write(2) execute(1). Sum desired values to give one digit permission value for each set • Read write and execute 7, Write 2, Read and Execute 5 • Adding or removing particular permissions • Add execution permissions for user chmod u+x filename • Remove write permissions for other chmod o+w filename • Add read permissions for everyone chmod a+r filename

44. File Permissions Examples • chmod u-x filename • (remove owners execute permission) • chmod a+w filename • (make the file readable for all users) • chmod 644 filename • (make the file readable for all users but writeable only by the owner) • chown newowner filename • (you must own the file or be root) • chgroup newgroup filename

45. Processes • Command & • Run command as a background process • cntrlZ • Suspend (temporarily stop) foreground process • bgMove suspended process to background • fg Move background process or suspended process to the foreground • cntrlC • Terminate the foreground process

46. Processes • ps or ps -l • List information about all current processes • kill pidnumber • Kill background process with PID pidnumber • (use ps to find the pidnumber of the process) ps -l F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 8 S 37636 7058 7054 0 46 20 ? 273 ? pts/38 0:01 csh 8 S 37636 7072 7058 0 51 20 ? 296 ? pts/38 0:00 bash • To assure a process will die use kill -9 pidnumber