CIS 656 Students in CIS 656 will do a project that involves programming. See ``About CIS 656 etc''. In addition, much of the homework will involve if not programming, at least use of computers. I assume all students have access to a computer and are already ``computer literate''. The note below is for students who are not used yet to the NJIT computer set-up. All NJIT students have access to the computers afs1 , ... , afs36 in the ``Engineering Computing Laboratory I'', GITC 2305. Below I use ``nslookup'' as the prototype command you can use to play with. nslookup can be used to find the IP address(es) of a computer if you know its name, or to find its name if you know one of its IP addresses. nslookup will be discussed in class soon, but you can start playing right away. See the example below. I also assume all students have access to a computer at home and can use it to remotely access (log in to) NJIT computers. If that does not hold for you, there are some hints below. I strongly recommend that every student as soon as possible does the following (do not do those items that are old hat to you!). 1. Walk to GITC 2305 (Engineering Computing Laboratory I) and log on to one of the computers afs1 , ... , afs36 , using your afs user id and your afs password. That lab is open weekdays 8:00 am - 11:00 pm, Sat and Sun 10:00 am - 6:00 pm. afs1 , ... , afs36 are aliases. The ``real'' names are alizarin.njit.edu , ... , schiff.njit.edu . 2. Once logged on to ``afsx'' (x one of 1 , ... , 36), at the prompt, type nslookup afsy (y one of the numbers 1 , ... , 36 , I would choose it not equal to x). For example, on my own workstation: maan-1477 ott>: nslookup afs7 Server: dns1.njit.edu Address: 128.235.251.10 Name: bronfman.njit.edu Address: 128.235.205.35 Aliases: afs7.njit.edu maan-1478 ott>: The result tells me that the dns query (will be explained later) has been served by dns1.njit.edu , which has IP address 128.235.251.10 , that afs7 is only an alias and that the real name is bronfman.njit.edu , and that its IP address is 128.235.205.35 . 3. Play with nslookup. Check what happens if you type nslookup bronfman , nslookup 128.235.205.35 , nslookup 128.235.251.10 , etc. Find a computer outside of NJIT and find its name and IP address. For example www.lcs.mit.edu . Find the IP address of that computer. Note: practically, for every website like http://www.lcs.mit.edu/ there is a computer with the corresponding name www.lcs.mit.edu . 4. While logged in to afsx , at the prompt, type telnet afsy (y one of 1 , ... , 36 , not equal to x). You will be asked for login id and password again. Then while sitting at afsx you will have a window open to afsy . (You can do the same things with the official names bronfman etc.) Now, afsx acts as telnet client, and afsy acts as telnet server. All machines afs1 , ... , afs36 are configured to act as both telnet client and telnet server. While (remotely) logged on to afsy , at the prompt, type nslookup afsz (z : ...) and play some more with nslookup. Aside: afs1 - afs36 are solaris computers. They have ``time-sharing'' operating systems. That means that many users can be logged on simultaneously: One on the keyboard, several remotely (by telnet, rlogin, ssh, ...). You will hardly notice the presence of the others. 5. You can ``concatenate'' telnets: from afsx to afsy to afsz to ... . Try it. You even can go in circles! afsx to afsy to afsz to afsx , etc. 6. To go back: at the prompt, type exit This leads you back one computer. Ultimately back to afsx . If you type exit once too often, you get logged off and have to log on again. (Or only open another window: depends). 7. When back at the original afsx , at the prompt, type ssh afsy . (You may have to give your password again, maybe not). Now afsx is the ssh client and afsy is the ssh server. Do the same playing you did in 5 , 6 . ---------------------------------------------------------------------- 8. Go home and remotely log on to one or more of the afsx computers. You can use dial-in, or telnet. You may also be able to use rlogin or ssh or vpn. For dial-in or vpn (and some of the others?) see http://telecom..njit.edu/ For dial-in you need a modem. For the others, you need to already be ``on the web''. (Possibly through a modem and connection to your ISP. Possibly through Cable Modem, or DSL Modem) To use telnet, your computer must be configured as a telnet client. It almost certainly already is. If you have a PC, open an MS-DOS window and at the prompt type telnet afsx.njit.edu (x: your preferred number in 1 , ... , 36). Then you have to give your afs user id and password, and you will be logged in to afsx . To use ssh , your computer must be configered as an ssh client. To download the ssh software, see http://distrib.njit.edu/ (Or go to Google and search for ssh , then download and install the free software). 9. Once you are logged in from home, play with nslookup as before. You can also concatenate connections: from home to afsx , to afsy , etc. Type exit to go back. (Once too often and you are back in your PC at home). 10. Try to do nslookup in your PC itself. I am sure MS has something like nslookup . But nasties as they are, they may have changed the name. Let me know how it works. When logged in to afsx , either ``on the spot'' or remotely, you have access to your afs directory. Play with it. Create and save some files. create subdirectories. Read and answer your Email. etc.