Practical TCP/IP Niall Mansfield

Categories: Computing

Disabling compression in an HTTP session

Sometimes you want to see what's happening in an HTTP session, but a normal tcpdump or wireshark trace isn't very helpful because the data is compressed, so what you see appears to be gobbldygook.

You can get round this by disabling compression in your browser. In Mozilla Firefox:

• Type about:config in the search box. This gives you access to Firefox's detailed config settings.
• Look for network.http.accept-encoding (by typing it into the Filter box.)
• Double-click on the entry that's displayed, to open the Enter string value dialog.
• Delete the value and press OK.

Now when your browser connects to an HTTP server, the browser will not say that it can handle compressed data, so the server will send it in clear, and you can see what's happening.