While many (but not all) users are familiar with the concept of security software, there are more basic ways to protect unwary surfers from phishing sites, botnets, intrusive advertising and other unwanted visitors: DNS services.
First, a quick primer for those who are unfamiliar with DNS: You utilize the Domain Name System (DNS) every time you surf the Web. Each time you type a site name into the browser, DNS is queried for the IP address corresponding to that particular domain, so the browser can contact the Web server to get the content. (The process of converting the domain name to its IP address is called domain-name resolution.)
There are actually two main types of DNS servers: recursive and authoritative. The ones that are used by most individuals and small companies (and that are covered here) are called recursive DNS and are the default services provided by most Internet Service Providers (ISPs). All the companies listed here offer recursive DNS services. Some of them, however, also sell authoritative DNS services, which allow website owners or hosts to define the Web server IP addresses that their domain names point to and to manage other DNS settings.
Since DNS servers are the middlemen between your browser and website content, there are many third-party DNS services that offer additional functionality for both users and network administrators. These tools can include:
- Content filtering. This can be conveniently implemented to block adult sites and other unwanted content, while requiring no software on the computers and devices.
- Malware and phishing blocking. This can be performed by the content filtering tool also, to block sites containing viruses, scams and other dangerous content.
- Protection against botnets. This blocks communication with known botnet servers so your computer isn't taken over.
- Advertisement blocking. This is another type of content filtering, which some DNS services specifically concentrate on.
- URL typo correction. For instance, if you typed gogle.com it would correct to google.com .
In this article, I identify and describe several of these services. Many -- in fact, most -- are either completely free of charge or offer a number of free features that might make it worth your while to take a look.
Because there are so many DNS services available, for this list I chose those that provide some type of automatic or preconfigured content filtering (and I describe where you are sent when the filter kicks in, which can range from a straight "nothing to be found here" page to an ad-filled cacophony).
It's easy to switch to a different recursive DNS service. Simply change the IP addresses for DNS in the Internet settings of your router to apply it to the entire network, or change the DNS settings on select computers or devices. Without further intervention, you'll receive the DNS service's preconfigured security or filtering protection. Some services also allow you to create an account to customize the level of protection and messages that appear when a site is blocked.
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