Difference between revisions of "DNS"

Revision as of 10:48, 21 August 2015

What is DNS?

Overview

DNS stands for Domain Name System, it is a protocol within the set of standards for how computers exchange data on the internet and private networks. A simple explanation would be it is responsible for turning a recognizable name like xmission.com into a IP address like 198.60.22.4. You use DNS everyday and may not be aware of it. From a simple email to visiting your favorite social network. In the background your computer connects to a DNS Server or Name Server which manages a database that maps domain names to IP addresses.

When you connect your desktop or laptop computer to the internet, most of the time you get an IP address that comes from a DHCP server on your network. The job of this DHCP server is to make sure your computer has a IP address and other network configurations it needs to give you access online. Normal circumstances when you connect your computer to the internet you will be using XMissions DNS. This is done automatically when you connect. You can refer to this as your Primary DNS.

If you run a business we know that having a reliable connection to the internet is essential. Down time as we all know means loss of sales and unhappy customers. In a perfect world we would never have an outage, however outages can and do occur. Having a backup is not something that we thing of until it is too late. DNS resilience is determined by the steps you take to ensure your business, or home network is available to the internet. Setting up primary and secondary DNS servers is key to keeping you online.

There are many public DNS providers like OpenDNS and Google's Public DNS that allow you to use their free service as a primary or secondary DNS. Setting them up will take a little configuration on your side, however in the end if there is an outage on your primary DNS your secondary will kick in for redundancy.

Advanced

• What is the Primary DNS Server?

XMissions Primary DNS server is 198.60.22.2. This server is responsible for any new entries and updates from DNS zones. It holds the "Master Copy" of all DNS records.

• What is the Secondary DNS Server?

XMissions Secondary DNS server is 198.60.22.22. This server is mainly for redundancy. It will simulate what is on the Primary DNS server and relatively act the same as our Primary DNS server.

• What are tertiary, quaternary, quinary, senary, septenary, etc. DNS Servers?

These servers are for pure redundancy. You can have many other DNS servers for your connections. Typically these servers are typically offsite, whereas our DNS servers are onsite. If both XMissions Primary and Secondary DNS servers go down, thats when these DNS servers will kick in. Popular providers for this kind of service is OpenDNS and Google's Public DNS.

• What is DNS Caching?

DNS Cache is a database of all domain names. It's purpose is to translate domain names to IP addresses. For example, the database will translate xmission.com to 198.60.22.4. Occasionally, there may be issues with a DNS server caching information that is no longer valid. A DNS Flush will update the information to be valid. If you need to manually flush your DNS on your computer, here's how:

Windows DNS FLush

Windows Vista/7

Click the start button on the bottom left of your screen and navigate to the command prompt (Start > All Programs > Accessories > Command Prompt)

Make sure that you right click on the command prompt application and choose "Run as Administrator"

Type in the command ipconfig /flushdns

Windows 8/8.1

Ensure that you're on the Windows 8 Start Screen.

Simply type cmd and the Windows search bar will appear on the right hand side with search results.

Right click on Command Prompt and click Run as administrator.

Type in the command ipconfig /flushdns

Windows 10

Click the start buttom on the bottom left of your screen, and type in "cmd".

Right click on the command prompt application and choose "Run as Administrator"

type in the command ipconfig /flushdns

Mac OSX DNS Flush

Yosemite

Mac OS X 10.10, you need to do the following:

Open up the command terminal.

Run the command sudo discoveryutil udnsflushcaches

Lion, Mountain Lion, Mavericks

Mac OS X 10.7, 10.8 or 10.9, you need to do the following:

Open up the command terminal.

Run the command sudo killall -HUP mDNSResponder

Snow Leopard

Mac OS X 10.6, you need to do the following:

Open up a command terminal.

Run the command sudo dscacheutil -flushcache

Leopard and below

Mac OS X 10.5.1 or below, you need to do the following:

Open a command terminal.

Run the command sudo lookupd -flushcache

Linux DNS Flush

Open up a command terminal

Run the command sudo /etc/init.d/nscd restart

XMission DNS

XMission provides basic and advanced name service options...

Basic DNS Setup

XMissions DNS: 198.60.22.2, 198.60.22.22. Any XMission connects should automatically obtain these two IP addresses when connecting to the internet, however, if you need assistance adding these to your connection, feel free to contact support. Toll Free: 1-877-964-7746 Local: 801-539-0852

Advanced DNS Configuration Options

While xmission's name service is very reliable we encourage businesses and individuals who prioritize always being online to consider some advanced configuration options including DNS caching and using an additional offsite service like OpenDNS and Googles Public DNS for redundancy.

Other DNS Options

OpenDNS

Probably the oldest that are still around. They offer a variety of free and paid services. Their IP address are 208.67.222.222 and 208.67.220.220

OpenDNS configuration guide

Google Public DNS

You may have see these number or heard of them and didn't know what they were. Well now you know Google Public DNS IP address are 8.8.8.8 and 8.8.4.4

Google Public DNS configuration guide