August 28, 2000
By Karen Kenworthy
IN THIS ISSUE
Many thanks to all who wrote to me after my accident. Fortunately, I still feel fine. Despite the entreaties of several lawyers, I appear to have escaped unharmed. :)
My van wasn't so lucky, but thanks to my wonderful mechanic, it's completely healed. After a couple of weeks of forced isolation, it's great to be able to roam the neighborhood, in air-conditioned comfort, once again.
Unfortunately, despite having my van back, the secluded Power Tools Workshop feels more secluded today than usual. That's because my Internet connection is down. For the third time in a week, no e-mail flows, and no Web sites can be visited. All I can do is sit here and write my column. :(
My poor little servers are also wondering what to do next. Normally, they host several small Web sites, everything from my teddybear.com, to my high school reunion site, to a site I operate for my family, plus a few sites I host for friends. I even find time to use my Web servers for business, hosting sites for a few programming clients.
Without their connection to the Internet these sites go dark. Worst of all, they may be unreachable for hours without my knowing it. Contrary to the rumors some are spreading, I do sleep from time to time. And even when awake I'm not always "on" the Internet. I may be out seeing the world, through the windows of my van. Or I may be enjoying some time with friends. I even write programs or work on database projects. So sometimes I'm the last to know when there's a problem with my Internet connection.
There was a time when this would be a personal problem. After all, how many people host a Web site? How many people count on their Internet connection working 24x7? The answer to both questions is, quite a lot of us. Many Internet Service Providers (ISPs) provide subscribers a personal site on the Web. Other companies offer free Web sites, in exchange for a little advertising banner at the top of each page.
And more and more small businesses have Web sites these days. Some provide a bit of company information, while others are full-blown e-commerce sites, taking orders, answering customer questions, reporting inventory levels, and more. Companies also use Web sites to communicate with employees, contractors, customers, and even the press.
Whether these sites are hosted by a third-party, or run on computers sitting in the company's office, they have one thing in common. We depend on them being available all the time. Oh, and they have one other thing in common. Because phone companies, Internet Service Providers, webmasters, system administrators, and all the other people and companies responsible for the Internet are human, or employ humans, these Web sites will occasionally go down.
Sometimes, when problems occur, a quick call is all that's required to set things right. Perhaps someone at the ISP has pulled the wrong plug. Or someone at a phone company has flipped the wrong bit, inadvertently changing a setting. An important piece of hardware may have failed, breaking your link with the outside world. Whatever the reason, the first step to fixing a problem is knowing one exists.
That's why I recently wrote the Winmag.com 'Net Monitor. This new Power Tool periodically tries to contact a Web site of your choice. If the contact is successful, it then attempts to download one of the Web site's pages. If this effort succeeds too, the site is working and all is well.
But if the Monitor's attempts fail for any reason, the time and reason for the failure is displayed in the program's main window. There are several problems the Monitor can detect, including:
Unable to resolve domain name.
As you know, computers on the Internet are assigned unique numbers, called their IP address. These numbers look like this: 126.96.36.199. But you and I know computers by their names, names like www.teddybear.com. To resolve this difference, special computers called Domain Name Servers (DNS) are scattered across the Internet. When provided a computer's name, they respond with its IP address. If no Domain Name Server can be contacted, or if the ones that can be contacted are unable to translate a computer name into its IP address, the 'Net Monitor will report "Unable to resolve domain name."
Unable to Connect
This error message indicates a computer's IP address has been determined. But the computer at that address is not responding to the Monitor's attempts to contact it. The remote computer may be at fault, or our connection to it via the Internet may be broken.
Unable to Retrieve
This error message indicates we have connected to the remote computer. But the remote computer has refused our request for a Web page. This may indicate the remote computer's Web server is not working. Or it might indicate we're asking for a page that doesn't exist. Additional information displayed by the 'Net Monitor (Access Forbidden, Page Not Found, etc.), usually provides more information.
This last test determines whether the page retrieved from the remote server is the page we expected. To accomplish this, you must first embedded a comment anywhere within the page being retrieved. The comment should look like this:
<!-- - - 'Net Monitor - - -->
Of course, to do this you must be able to modify the content of one of the Web site's pages. But if you do, the 'Net Monitor can look for this comment in every page it downloads. If the comment isn't there, the Monitor can report this as an error, indicating the Web server being monitored has delivered the wrong page.
There's more to say about the new 'Net Monitor. And with your help, there are probably a lot of features to be added. But if you'd like to take 'Net Monitor v1.0 out for a ride, you can download your free copy at https://www.karenware.com/powertools/ptnetmon. The programmers among us may want to download the program's free Visual Basic source code too. In addition to my usual VB gems, this program's source code shows how a program can download a web page, and monitor the progress of the process.
And if you do drop by my site for a visit this week, be ready for a little surprise. To escape from the "Setup Swamp," I'm experimenting with a couple of new setup programs. One is used for the first time, to install the 'Net Monitor. The resulting setup program, ptnetmon-setup.exe, is a bit larger than the old setup programs I've been using. But it should eliminate a number of install and uninstall problems.
Of course, you and I will be the final judge of that. We'll talk more about setup problems, and how to solve them, after we've all had time to give these new setup programs a try.
Until then, look for me back on the 'net soon. And when I do get back online, if you see me, be sure to wave and say "Hi!"
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