OpenDNS is an alternative to the default DNS service provided by your ISP. It is secure, fast and has no blacklisting as applied by your ISP. This has made it an extremely popular service and it is used widely in schools, colleges and at other places.
The OpenDNS website describes itself as,
OpenDNS is the leading provider of free security and infrastructure services that make the Internet safer through integrated Web content filtering, anti-phishing and DNS. OpenDNS services enable consumers and network administrators to secure their networks from online threats, reduce costs and enforce Internet-use policies. OpenDNS is used today by millions of users and organizations around the world.
OpenDNS has become extremely popular over the last three years after its launch in 2006. It serves 20 million requests. This has upset ISPs because OpenDNS feeds off their business and takes away part of their possible profit.
OpenDNS founder David Ulevitch has raised concerns over blocking of OpenDNS by Verizon Sprint Wireless and has said,
They do not want to see DNS traffic, queries and data streams leaving them. In the way we have monetized domain name services, they want to do what we do. However, they are not an opt-in service like we are, and they can also block us, which is what we are concerned about. And they try to block us in crafty ways. There was a report of an ISP working group whose members said that for “security” reasons, they should block alternative DNS services.
This autonomous decision by Verizon Sprint Wireless will bring it a considerable amount of negative karma. Blocking an alternate DNS service is going too far out in the competition.
Update: OpenDNS founder David Ulevitch has said that it was not Verizon Wireless blocking them but Sprint Wireless. Read here for his reaction.