No, certainly not cheaper (for any value of cheap). I haven't measured but I can't see how it would be possible, as in the first case the network stack takes ca

No, certainly not cheaper (for any value of cheap). I haven't measured but I can't see how it would be possible, as in the first case the network stack takes care of it (in kernel land) and in the other case you have to go all the way back to userland. The reason I tried the transparent GIF trick is because some sites have frames with ads and whatnot and having the firewall refuse the connection will result in having an error message displayed in the browser. Not really aesthetically pleasing. While I don't care, because I know the reason it is displayed; some less technical people might start thinking their Internet is broken. In addition to that, the GIF results in a cheap form of "element hiding" since you end up replacing a 5050 banner with a 11 transparent square. Now that you mention it though, I wonder what would happen if I set the server to serve a null byte for instance.