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In this lecture, we’ll learn what root hints is and how it’s used in a Windows DNS server environment.
So, what is the Root Hints file?
- The root hints file contains a list of thirteen internet servers, and their IPv4 and IPv6 IP addresses.
- These servers are authoritative for the root domain.
So, what’s a Root Domain?
The root domain is a group of servers located at the top of the DNS tree.
So, where is the Root Hints file stored?
- The root hints file is located on the DNS servers hard drive. In the C:\windows\system32\DNS folder.
- So, if we click on the Cache file
Notice the IPv4 and the IPv6 IP addresses
- By default, Windows DNS uses these 13 Root hints servers to resolve queries that your local DNS server can’t resolve.
- Another method of resolution is to configure forwarders.
So, what are forwarders, and how do they work with root hints?
To take a look at forwarders, we will open Server Manager, then click tools, then DNS manager.
- To open forwarders right click on your server, then click properties, then click the forwarders tab.
- Forwarders are DNS servers that this server can use to resolve DNS queries for records that this server can’t resolve.
- Configuring forwarders is the manual method that will forward DNS queries for external DNS names to DNS servers outside your network.
- Notice that the box is checked, and beside the check box it say’s “Use root hints if no forwarders are available” Notice this setting is greyed out.
That means that if this check box is checked, you will be using this list of Root servers to resolve queries for zones that don’t exist on the local server.
Let’s go ahead and click edit and there is our IPv4 and our IPv6 IP address for this root server, A-root-servers.net
And this is the same list that I showed you that was on the C: drive of the DNS server.
Let’s go ahead and add a forwarder
- Click Forwarders
Now click the edit button, now type 8.8.8.8, which is the IP address for googles DNS server. Now click ok
Now we have 8.8.8.8 designated as our forwarder and notice that you can now check or uncheck the box.
- If we uncheck the box that means we won’t be using root hints for query resolution, we’ll be using our forwarder.
Put the check back in there. Now, we’ll click the edit button and remove the forwarder.
- Click our forwarder, then click delete, then click ok.
Let’s take a look at what could happen when we have root hints enabled.
- In a typical DNS installation, a client forwards a query to the local DNS server.
The local DNS server forwards the query to the DNS server on the DMZ network.
The DMZ’s DNS server forwards the query to the ISP’s DNS server.
Then the query would be eventually resolved on the internet.
- If the DNS server on the DMZ goes down.
Because root hints is enabled on the local DNS server, this server would try to resolve
queries on the internet using the root hints servers.
Which would be considered a potential security issue.
- To be sure that you understand the connection between forwarders and disabling recursion, we need to review the disable recursion option.
Let’s go ahead and open server manager, click tools, DNS manager, right click on our server, and click properties, now click the Advanced tab.
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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