Blocking Webpages

Hi,

I am currently running OSX 10.6.8 and have a question about blocking webpages.

I have come across the sudo nana hosts method to block webpages using the 127.0.0.1 method which works fine for facebook and other pages.

However, is there any way to block all pages within one network? For example, blocking http://www.tumblr.com will not block http://macrumors.tumblr.com.

Is there a way to block all tumblr sites?

Thanks,

I have tried that and it works for only tumblr.com and not any blog sites within the tumblr domain.

Is there something I am missing?

Thanks,