Ask an Engineer: DNS Servers

Ask An EngineerEarlier this month, a Comcast DNS Failure left millions of consumers without internet access in several huge tech markets. This was an inconvenience to millions and, even though Comcast recognizes the frustration enough to issue $5 credits to those affected, there were some folks who found a way around the DNS failure. To better understand what exactly happened and how some savvy consumers changed course to avoid the lapse in service, we’re turning to Len Cacioppo, VirtualPBX’s VP of Operations, for answers.

First of all, what is a DNS server?

It’s basically a phone book of the Internet. A DNS (Domain Name System) server has all of the locations or “phone numbers” of every website, email, what have you, and search engines like Bing or Google are the index.

If there are other DNS options out there, why does Comcast have their own that can potentially go down?

It’s all about the speed of service for the end users. There are a bunch of different DNS options available, but if you can use your internet service provider (ISP), that will mean that users have to wait less time for pages to load, media to stream, etc. This may be only the smallest fractions of a second for some things, but in the end it really helps improve performance.

What does it mean when the DNS goes down? How does that happen?

Typically, no service provider is going to be completely upfront about what causes a failure because it would be difficult to do so without yielding too many trade secrets. That said, these events are typically some sort of internal error where an application, network, or service has failed. These events can be a result of any one of numerous factors from a DDoS attack to a power outage without redundancy (backup points). It’s impossible to say what caused this recent one.

What are Google DNS and OpenDNS and how can they be free? How do people sign-up for them?

DNS isn’t something that is really commercialized at all, it’s almost like radio airwaves. DNS is administered through an international consortium of companies deciding to provide the service, and not all of them choose to sell it or, like Comcast and other ISPs, include it in their service for internet access. Free DNS servers don’t really require a sign-up, they just require that you include these other “phone books” in your computer’s list of references to check when you are online.

How can people fix this if it happens again or possibly even avoid it causing a disruption in the future?

DNS Back UpsThis is pretty simple. All you have to do is find some other DNS information (which is widely available for free on the internet) and put them into the Network Settings of your computer. Here you can see we’ve put the DNS information for Google, AT&T and a few others right into our settings. This way, should our ISP have complications on their end, we will simply perform “phone book” lookups through the next DNS server on the list and so on. If there were to be a failure that compromised all of these, or your problem with the internet is access as opposed to services, chances are there’s no internet access via your ISP, so none of this would help anyway.

Many private customers wouldn’t have had this type of redundancy in place to protect them from the Comcast DNS outage, but steps like these are simple to take. Businesses, especially, should consider taking a few minutes to train employees to input back-up DNS options into their work computers so that work can keep humming along, no matter what happens.

To learn more about DNS servers, ISP, or any other internet issues that could help or hurt your business, get in touch with our hosted telecommunications experts today.

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