DNS filtering

Advertising can be blocked by using a DNS server which is configured to block access to domains or hostnames which are known to serve ads.

Morally, while some argue that domain name holders are owners of property (and have been found to have such rights in most developed countries), it has also been one of the web's most basic features that DNS can be localized and run on client, LAN, provider and national services. China, for instance, runs, its own root DNS and the EU has considered the same. Google has required their Google Public DNS be used for some applications on its Android devices. Accordingly, DNS addresses / domains used for advertising may be extremely vulnerable to a broad form of ad substitution whereby a domain that serves ads is entirely swapped out with one serving more local ads to some subset of users. This is especially likely in countries, notably Russia, India and China, where advertisers often refuse to pay for clicks or page views. DNS-level blocking of domains for non-commercial reasons is already common in China.