If a Web site is inaccessible, how can your tell where the problem lies, and if there is anything that you can do to fix it? In part 1 of this article, I explained some basics about how your Internet connection works, and described how to "ping" a site http://www.auctionbytes.com/cab/abu/y203/m05/abu0094/s03. In part 2, I discussed trace routes. http://www.auctionbytes.com/cab/abu/y203/m05/abu0095/s04.

In this article, Part 3, I will explain the challenges of checking a site like eBay, I'll list some resources that will allow you to check your connection online, and share some great (some free!) programs that will teach you more than you ever wanted to know about connectivity.

Checking to see if eBay is down, or if there is a problem en route, poses its own set of challenges. Because of past DOS (Denial of Service) attacks on sites like eBay and Microsoft, both have firewalled webservers, which means that you cannot actually ping the main sites or run a traceroute directly to them. You can, however, run a traceroute up to their network and see if there are any issues before you get to eBay. If it looks clear up until the point you reach eBay's firewall, you can pretty safely assume that the issue lies somewhere within eBay's network.

Another solution I've come across to see if eBay is up is to use an "Anonymizer" to test your access the site. Anonymizers allow a user to hide their IP address on the URL they are going to, so no footprints can be traced back to them, except on the anonymizer itself. One side benefit of an anonymizer is that it directs you to a site via a different route than the one your ISP sends you through. Free anonymizers tend to have very fleeting lives on the Internet. Most now offer premium services and charge fees to use them. There are a few freebies still hanging around, but no there are no promises that you'll be able to reach them next week. I've listed a couple below.

The fact that hundreds of thousands of sites are available at our fingertips is amazing. We may take for granted what a complex system we're accessing when we fire up our computers and begin surfing the Web, so it's understandable that things don't always work the way they should.

If you make your living on the Internet, understanding how to detect problems can be a real advantage. And don't forget, you can still ask around in forums to see if anyone else is having access problems.

If you have other suggestions about testing your connection, there is a discussion going on in our forums at http://www.auctionbytes.com/forum/phpBB/viewtopic.php?t=4519

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Ping and Traceroute Utilities

Sam Spade A "Swiss Army knife" of tools, SamSpade includes ping, traceroute, finger, DNS lookup, tons more. A great utility! http://www.samspade.org Download program at: http://www.samspade.org/ssw/download.html

VisualRoute Server Provides a graphical traceroute from this server to any other network device you choose, useful for pinpointing network connectivity problems and identifying IP addresses. http://visualroute.visualware.com

Anonymizers

IDZap Anonymizer Requires a username (freespeech) and password (freespeech). http://fr0.idzap.com/index.php

TheCloak.com Free Anonymous Web Surfing http://www.the-cloak.com/login.html

Anonymizer Anonymizer private surfing. Free tool at top of home page, does not allow you to connect to eBay. http://anonymizer.com

More Network Diagnostic Tools

Allegiance Internet Looking Glasses for Public NAPs. Great for seeing if a region is having Internet problems. http://nitrous.digex.net

IP Address Locator Tool IP Address Map lookup service is provided for free by Geobytes Inc. to assist you in locating the geographical location of an IP Address. http://www.geobytes.com/iplocator.htm

The Internet Health Report Delivers data about network performance between major U.S. Internet backbones. http://www1.internetpulse.net

Pingplotter A network troubleshooting and diagnostic tool. http://pingplotter.com