Sign up to access this lesson
Click here to sign up and get access to this lesson!

Saving Progress...
So, what is Round Robin?
It’s a method of load balancing that enables you to spread the network load between servers on your network.
For example, let’s say I have three WEB servers hosting the same content with three A host records.
All with the same name of SA but with different IP addresses.
The goal is to load balance between these three servers to help share the network load.
That’s exactly what Round Robin will do. I’ve created another record called a CNAME record. This record maps the alias name in this case, www to the true name sa.serveracademy.
From our DNS server. We can check the status of Round Robin and Netmask Ordering from Server Manager.
Let’s go ahead and open server manager, click tools, and DNS manager, from our server right click then click properties, then click Advanced.
And you can see that round robin and netmask ordering are both checked and enabled by default.
- Now I’ll show you how round robin works
- The 1st client will get the 1st address, then the second address, then the third address. The second client will get the 2nd address first, the third address 2nd, and the 1st address third. Then the third client will get the 3rd address first the 1st address second, and the 2nd address third and down the line.
The 4th client would get the 1st address again then back and forth and back and forth.
- So, the advantage of Round Robin is to ensure that there is load balancing anytime duplicate names are found with different IP addresses in the DNS environment.
- We can test Round Robin by opening a DOS prompt in administrator mode and typing nslookup, then pressing return. This puts nslookup in interactive mode.
- Now type www.serveracademy
- if you recall that is our CNAME record and press return
- Now press the up arrow key and press return.
Each time you press the up arrow key, and press return
your reloading the CNAME record, and you getting different results.
You can see that the WEB server IP addresses are rotating, and that round-robin is working as it should.
- But one of the disadvantages of Round Robin is that the DNS server never goes out to see if one of the servers is down.
So, if, for example, SA1 is down that means that 33% or more of my clients will attempt to connect and fail.
- So, this is not hardware load balancing,
- But it is there and provides this basic functionality.
Configuring Netmask Ordering
- One way you can enhance DNS Round Robin is by enabling NetMask Ordering
- So, what is Netmask Ordering?
Let’s go back to our example, Let’s say we have created one more webserver, an A record with a name of SA with an address of 10.0.1.10.
If we have one client on the 192.168.0 subnet, it will get the normal rotation of 1,2,3,4
Then the next client that shows up from the 192.168.0 subnet might get 2,3,1,4.
But if we have two more clients connect and their client IP address is on the 10.0.1.0 subnet, the SA4 server will always be the most preferred server.
Anything in this subnet will always be on top of the list.
But these two clients on the 192.168.0 subnet will never get the address for SA4 at the top because they belong on the wrong subnet.
For those two clients, 10.0.1.10 will always be the least preferred IP address.
Sign up to access the rest of this lesson
You must either log in or sign up to access this lesson.
CURRICULUM
Course Introduction • 10min
0 / 2 lessons complete
Instructor and Course Introduction
Video | 7 min
What's New in Windows Server 2016 DNS
Free lesson
Video | 3 min
DNS Basics • 56min
0 / 8 lessons complete
What is DNS
Video | 3 min
Installing the DNS Windows Server Role
Video | 6 min
Building DNS Server Quiz
Quiz | 10 Questions
The Hosts File
Video | 4 min
DNS Console Overview
Video | 7 min
Recursive and Iterative Queries
Video | 8 min
DNS Basics LAB
Video | 10 min
DNS Basics Quiz
Quiz | 8 Questions
DNS Resource Records • 45min
0 / 5 lessons complete
DNS Resource Record Types
Video | 3 min
Creating the mytestzone Forward Lookup Zone
Text | 2 min
Creating DNS Resource Records
Video | 4 min
Creating DNS Resource Records Lab
Lab | 30 min
DNS Resource Records Quiz
Quiz | 7 Questions
DNS Zones • 4hr 11min
0 / 12 lessons complete
DNS Zones
Video | 4 min
Creating a Forward and Reverse Lookup Zone
Video | 5 min
Creating a Secondary Zones
Video | 9 min
Stub Zone Creation
Video | 11 min
Active Directory Zone Replication
Video | 12 min
Implementing DNS Forwarding
Video | 8 min
Implementing Conditional DNS Forwarding
Video | 7 min
Forward and Reverse Zone Creation Lab
Lab | 60 min
Creating a Secondary Zone Lab
Lab | 30 min
Conditional Forwarding Lab
Lab | 60 min
Creating a Stub Zone Lab
Lab | 30 min
DNS Zones Quiz
Quiz | 15 Questions
DNS Delegation • 50min
0 / 4 lessons complete
Domain Name System and DNS Delegation
Video | 7 min
Windows 2016 Server and DNS Zone Delegation
Video | 8 min
DNS Delegation Lab
Lab | 30 min
QUIZ - Domain Name System and DNS Delegation
Quiz | 5 Questions
DNS Security Techniques • 36min
0 / 5 lessons complete
DNS Security Techniques Overview
Video | 9 min
Configuring DNS Cache Locking
Video | 5 min
Configuring DNS Socket Pools
Video | 6 min
Configuring Response Rate Limiting
Video | 8 min
DNS Security Techniques Quiz
Quiz | 8 Questions
Advanced DNS Topics • 22min
0 / 5 lessons complete
Overview of Advanced Topics
Video | 1 min
Enabling Round Robin and Netmask Ordering
Video | 5 min
Configuring Recursion
Video | 4 min
IPV4 and IPV6 Root HInts
Video | 6 min
Advanced DNS Topics Quiz
Quiz | 6 Questions
DNS Security (DNSSEC) • 1hr 16min
0 / 6 lessons complete
Windows DNS Security Overview
Video | 7 min
Symmetric vs Asymmetric Encryption
Video | 5 min
Installing DNSSEC on Windows 2016 Server
Video | 12 min
DNSSEC Client Install
Video | 7 min
DNSSEC (DNS Security Lab)
Lab | 30 min
DNSSEC Quiz
Quiz | 15 Questions
DNS Policies • 55min
0 / 6 lessons complete
DNS Policies Background Information
Video | 8 min
Configuring DNS Filtering
Video | 7 min
Configuring Split Brain DNS in an Active Directory Environment
Video | 12 min
Configuring DNS Selective Recursion Policy
Video | 7 min
Configuring a Traffic Management Policy
Video | 11 min
DNS Policies Quiz
Quiz | 10 Questions
PowerShell for DNS • 1hr 27min
0 / 6 lessons complete
PowerShell for DNS Part 1
Video | 2 min
PowerShell for DNS Part 2
Video | 5 min
PowerShell for DNS Part 3
Video | 10 min
PowerShell for DNS Part 4
Video | 5 min
PowerShell for DNS LAB
Lab | 60 min
Powershell for DNS Quiz
Quiz | 5 Questions
Troubleshooting DNS Issues - Troubleshooting Tools • 1hr 39min
0 / 8 lessons complete
Troubleshooting Tools Every IT Pro Must Know
Video | 9 min
The Events Viewer Overview
Video | 6 min
Subscriptions
Video | 9 min
Monitoring and Debug Logging
Video | 9 min
Trouble-Shooting DNS Client Issues
Video | 4 min
Troubleshooting Subscriptions Lab
Lab | 30 min
DNS Troubleshooting Lab
Lab | 30 min
DNS Troubleshooting Quiz
Quiz | 2 Questions