Re: Musings on Random Musings
Very briefly, as long as you're not entering numeric IP addresses directly, your machine ALWAYS consults a DNS to run the URL into the numeric IP. And the machine ALWAYS checks its Hosts file first, a local file in a designated place with a list of server names and their associated IP numbers. Most people have no Hosts file or a one-liner, but it is possible to put others in. And, to the point, misdirect certain obnoxious servernames to point to the local host (that is, your own machine). That means that lots of ads will get 404 ("Not Found") errors quickly, but the obnoxious crap won't get through.
Here is a source for getting one into place.
The weakness is that new server names have to be added individually; there are no wild cards in that file syntax. The good part is that it's a flat-text file, human readable, so even mere mortals can know what they are letting themselves in for by looking at the file. There can't be any concealed back doors, though it's impossible to get completeness of coverage.