Why aren’t they blocking the workarounds?
Blocking some of the above workarounds is easier than others. Certainly, throwing lite.facebook.com in with the rest would be simple. But what about blocking OpenDNS or blocking Facebook by IP address? It’s easier, quicker, and cheaper to block Facebook by DNS than to block Facebook or OpenDNS by IP address. First, DNS requests are much less frequent than web content requests by nature of the data. Second, DNS requests are cached at many different levels making them even less frequent. Third, there are much fewer DNS entries for Facebook than there are IP addresses for Facebook to block. Not only are there many Facebook domain names, but each domain name such as www.facebook.com can actually map to hundreds of ever-changing servers around the world, which is a technique that big web sites use to distribute traffic and keep things going fast. IP filtering could slow down internet traffic in Vietnam, which is not the case for DNS filtering. It’s reasonable that ISPs would try to discoura
