Public DNS and the Facts

What is Public DNS and Why Should You Use It?

DNS stands for Domain Name System. Suppose you type facebook.com in your browser’s address bar and press Enter. Your beloved Facebook opens—missing it for even a day might make you lose your cool. You typed, pressed Enter, and within a second, Facebook loaded. But within that one second, a lot happened. Your browser sent the typed facebook.com to a nameserver via the internet and asked, “Hey, which server hosts this site?” The browser and all intermediary systems recognize IP addresses. For example, Facebook’s IP is 173.252.110.27. Multiple sites can share the same IP. DNS’s job is to convert the alphabetic domain into a numeric IP and connect your browser to the server hosting that IP.

This DNS service is also run by some server. We usually don’t even think about it. Typically, the ISP (Internet Service Provider) that gives you internet access handles DNS resolution. Your computer’s operating system—especially Windows’ Local Area Connection or Wireless Area Connection—automatically finds the ISP’s DNS. That’s why when you buy a new domain, it can take hours or even days for its information to reach your local ISP’s server.

Beyond your ISP’s DNS servers, there are organizations that offer DNS services either free or for a fee. These are called public DNS. Google provides this service via their 4.4.4.4 and 8.8.8.8 nameserver IPs. OpenDNS is another such service. So if your ISP—like Grameenphone, Banglalion, or Link3—is offering DNS for free, why would you opt for a paid or alternative DNS service?

Speed:

In most cases, you’ll get faster browsing speeds using public DNS. Think about it—wouldn’t an international-grade service resolve and serve a site faster than your local ISP’s server? However, this depends on many factors, including your geographic location. So you might not always experience a speed boost.

Security:

There are millions of websites in the world. Many are great, filled with quality content. But some can unknowingly spread malware, viruses, spyware, etc., to your computer. They can steal your credit card or bank info and leave you devastated. Your personal privacy can be compromised in seconds. Google and other public DNS providers have systems to block such harmful sites and prevent them from displaying on your computer. Now ask yourself—does your ISP care about these things?

Reliability:

A DNS server needs regular maintenance, quality hardware, and skilled personnel. Given the state of services in Bangladesh, can your ISP guarantee that? Sometimes you’ll notice 2–4 sites won’t load. That’s because their DNS server can’t handle the load or fails to resolve DNS in time due to poor management. In such cases, public DNS servers are more reliable.

Open Web:

Governments sometimes block websites, and most of the time this is done at the ISP-level DNS server. Since public DNS doesn’t follow your ISP’s restrictions, you should be able to access those blocked sites. For example, when Facebook was blocked in Bangladesh three years ago, using a public DNS would’ve allowed access without needing proxy servers or tunneling.

Protection from Phishing:

Phishing means “fishing,” and in internet terms, it’s like fishing in murky waters. Suppose you’re on Facebook’s landing page and enter your password. The next day, your account is hacked. Sometimes hackers or groups present a site that looks exactly like the original. You enter your username and password, and they steal your sensitive info. That’s how you become a victim. Public DNS services usually filter these phishing sites and prevent them from loading in your browser.

Now, why did I write all this? For the past few days, my internet connection has been causing browsing issues. Speed test shows 1.67 Mbps download speed—pretty decent. YouTube videos play at 1020 resolution without buffering. But some sites are hard to open, and some don’t open at all. I did ping tests and route tracing—no issues found. Later I realized it was a DNS problem. I had been using Google DNS for a long time. But even Google DNS sometimes causes trouble. Switching to my ISP’s DNS made browsing worse. Finally, enabling OpenDNS gave me a decent browsing experience.

So how do you enable OpenDNS? I haven’t explained it yet, but below are some images. Follow them and restart your computer at the end. Then see if your browsing experience improves. If not, just let your system automatically select the DNS server and continue using your ISP’s DNS.

You can also try using Google DNS. Different ISPs or internet connections may perform better with different DNS options—there’s no fixed rule. For Google DNS, the IPs are 4.4.4.4 and 8.8.8.8 respectively.

[Pic, CC BY-SA 4.0]