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Sams Teach Yourself Network Troubleshooting in 24 Hours, Second Edition by Jonathan Feldman

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Finding Your Firewall

If you know every detail about your firewall, skip this section.

Still here? Great. There are really two major issues here. First, you have to figure out whether you’re using a proxy server or a packet-filtering firewall. Second, you need to figure out whether user authentication is in use.

Assuming that you have a working browser, finding your firewall type should be no problem. Fire up your browser and load a fairly complex page off the Internet (one that takes more than a second or two to load). While that’s happening, get into a DOS prompt and type the following:

						netstat -a > before.txt
					

After that’s done, type this, but don’t press Enter yet:

						netstat -a > after.txt
					

Now switch to the browser and refresh the page. ...

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