If Google provides public DNS 8.8.8.8 and 8.8.4.4, who provides 4.2.2.2? [closed]
Solution 1:
4.2.2.2 is one of six (4.2.2.1 through 4.2.2.6) DNS servers run by Level 3 Communications, a Tier 1 ISP. These are supposed to be used by Level 3 customers only, although they have gone into general use over the years. Supposedly, they are officially discouraging people from using these DNS servers, as they are under no obligation to provide this service and can theoretically discontinue them at any time (whereas Google provides their DNS servers expressly for public use).
More information here.