Courses Wayne State University College of Urban, Labor, and Metropolitan Affairs Department of Interdisciplinary Studies Times' Harvest courses, Winter 2001     ( http://www.is.wayne.edu/drbowen/thw05) Times' Harvest Advanced Seminar (online)     ISP 3360, Section 010, Call Number 25265, 4 credits Times' Harvest Advanced Directed Study (online)     a) ISP 3340, Section 010, Call Number 25785, 2 credits     b) ISP 3340, Section 011, Call Number 25786, 4 credits	Instructor
	David R. Bowen 2311 A/AB Wayne State University Detroit, MI 48202	Daytime tel: (313) 577-1498 Evening tel: (248) 549-8518 FAX: (313) 577-8585 Home Page:     http://www.is.wayne.edu/drbowen Email: d.r.bowen@wayne.edu At Ford: 313-390-2155

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Last updated: 1/4/05
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Debugging Internet Problems

Even if you are on campus, five computers can be involved in your Internet connection to the IS web server (www.is.wayne.edu). If you are off campus, the number can be ten computers. If certain of these computers fail or are very busy, your Internet connection can fail, or you may be unable to establish a connection in the first place. Of course, two critical computers are the ones at the ends of the connection; your computer, and the IS web server. Some of the error messages you may receive are very misleading. But, being able to debug Internet problems can help you correct them yourself, work around them, recover from them, or get help.

Never assume that the computer administrators (and I am one of them - the administrator of www.cll.wayne.edu) are aware of problems and working to fix them. They have to find out somehow. If there is a problem, let the administrator know! Preferably by telephone. I am a good place to start.

How an web page gets to you:

1. You use your web browser to request a web page by
   1. Typing in the URL,
   2. Clicking on a link, or
   3. Using a bookmark
      The part between the "http://" and the next "/" is the Domain Name of the web server (computer - for this course, www.is.wayne.edu) that you are requesting the web page from. The stuff to the right of the Domain Name tells that web server which web page (computer file) to send to you. The Domain Name uniquely identifies a computer connected to the Internet, the web server.
2. Your browser contacts a Domain Name Server (DNS) computer to translate the Domain Name into a numerical IP Address (for the IS web server, for example, 141.217.12.23). The DNS replies with the IP address.
3. Your browser contacts the web server by IP Address to request the page. The request is forwarded along the way by Gateways (computers, usually not the "Gateway" brand name) at both ends of the connections, and Routers in between. If you have recently requested that same page, your browser actually first requests the date of the page, and if that date has not changed since your last request, your browser fetches the copy it keeps in its cache.
4. The web server replies with the requested information, which travels using the same system of Gateways and Routers, but perhaps using a different return path.

During a given web session (from the time you open your browser until the time you close it), the browser remembers the numerical IP Address, so the DNS is not needed again.

This system is "the Internet", and the web is just one application that uses the Internet. Technically, the Internet is just a "pipeline" for information and it can carry many forms of information of which the web is just one. Email is another form of information. Historically, there were many earlier forms which are becoming less used but still exist. To use the Internet, you need an Internet application at either end of the connection, that speak complementary languages (or that "use the same protocol").

This is a complex system, and things can go wrong at many different points. That it works as well as it does is a tribute to the fundamental design, which offers many alternatives without user intervention, and so is "fault tolerant."

I also run an online web server monitor that reports the state of various WSU web servers. The monitor is available at http://server.monitor.wayne.edu.

Problem: You are using the WSU Internet service to dial on to the Internet with your Access ID and Password, but your Password, which worked at least once in the past, is not accepted.
	Possible Solution: The "Authentication server" is down or the connections to it are down. Call WSU Network Operations Center at (313) 577-4746 to ask if the authentication server is down, and possibly report the problem. For problems getting your computer set up to use the WSU Internet service, call the WSU computer help desk at (313) 577-4778.
Problem: when first connecting to the IS web server, you get an error message similar to the following: Depending upon your web browser make and version, this error message may simply say that this server cannot be located.
	This error message is incorrect; this server does have a DNS entry and can almost always be found. Possible solution #1: you have misspelled (not the case if you are using a bookmark that worked at least once before. Possible solution #2: your Internet connection has failed. Broadband connections do not usually fail, but dialup fails regularly. Try connecting again (for example, if you have a modem, disconnecting and redialing). Possible solution #3: The WSU "DNS server" is down. Call WSU Network Operations Center at (313) 577-4746 to ask if the DNS server is down, and possibly report the problem.
Problem: You want to use the web server, but the DNS server is down (see above).
	Solution #1: Bypass the DNS server and use the numeric IP address directly by using the URL http://141.217.12.23
Problem: You get an error message that says or includes "The server is not responding" or something similar.
	Diagnostic #1: Try connecting to another WSU web server, for example using http://www.wayne.edu or http://noc.wayne.edu. If these do not respond (same error message), then go to Diagnostic #2. Diagnostic #2: Try connecting to a non-WSU web server, for example using http://www.yahoo.com or http://www.ibm.com. Possible Solution #1: If only the IS web server is not responding, get in touch with me (David Bowen). For a quick fix, the telephone is much better than email, but if you are not going to call, then email, but that could take a day or two. Possible Solution #2: If several WSU web servers are down, then there is a good chance that the whole campus is down. Call WSU Network Operations Center at (313) 577-4746 to ask if the campus Internet is down, and possibly report the problem. Possible Solution #3: If you cannot reach anything on the web, check that your Internet connection is still working. As a last resort, call your Internet Service Provider (if WSU is your Internet Service Provider, this is the WSU Network Operations Center at (313) 577-4746) and explain your situation, and possibly report a problem.
Problem: You want to use the computer conference, but the IS web server is down, so you can't get to the link to the computer conference. Only the IS web server seems to be down; the other WSU and non-WSU web servers are responding.
	The conferencing server is actually a separate server running on the same computer as the web server, and the conferencing server has never been known to go down. If you have bookmarked the conference (highly recommended - bookmark the screen after you have logged in and gotten the number of new messages), use that bookmark. If not, go directly to the conferencing server using the URL http://www.cll.wayne.edu:8080/~1/
Problem: You were typing a long message into the conference, and you got an error message saying that your Internet connection is down, and possibly asking if you want to reconnect.
	Don't panic! Do not use the back button or do anything else besides the following: dial in again, then proceed as if nothing happened. The "information pipeline" connecting your computer and the web server has sprung a leak or gotten busted. If you don't tell the dumb computers on either end - your computer and the web server - they won't know, and when you fix the information pipeline by dialing in again, they will pick up as if nothing happened. However, if this makes you nervous, perhaps you should learn to compose your messages in Notepad and copy/paste them into the conference.