Typical TCP/IP Troubleshooting

The applications that make an intranet run are similar in nature to the applications that you’ll run on the Internet, so you can apply the techniques discussed in the following sections to your Internet servers as well. Here’s a good rule of thumb: The Internet is your intranet writ large.

It goes without saying, but I’ll say it anyway: Do not start troubleshooting at a TCP/IP level (layer 3 of the OSI model) until you have verified that layer 1 (physical) and layer 2 (data link) are okay. There’s no sense in chasing after a TCP/IP problem if your connectivity problem has been caused by your Ethernet switch blowing a fuse! (See Hour 17, “Where Do You Start?” for more info on problem triage, including basic TCP/IP ...

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