How Do I Set Up DNSSEC In 2024?

Introduction

The Domain Name System (DNS) is an essential to the structure of the internet. It’s responsible for translating human-readable domain names into IP addresses that machines can understand. As the internet has grown, so has the need to ensure the security and integrity of DNS data. This is where DNSSEC, or Domain Name System Security Extensions, comes into play.

In this guide, we will be focusing on helping you understand and set up DNSSEC. Our goal is to provide you with the knowledge and tools you need to enhance the security and trustworthiness of your DNS infrastructure. By implementing DNSSEC, you’ll be taking an important step in protecting your online presence against various attacks which can have serious consequences for your website and its visitors. So, let’s dive in and explore the world of DNSSEC.

Understanding DNSSEC

As you explore deeper into the intricacies of DNSSEC, it’s important to understand its definition and purpose. DNSSEC is an extension to the DNS protocol designed to ensure the integrity and authenticity of DNS data. By using public and private keys, along with digital signatures, DNSSEC provides a method for validating that the DNS information you receive is genuine and has not been tampered with.

In DNSSEC, there are several key components to be aware of, such as DNSKEY, RRSIG, DS, and NSEC/NSEC3 records. These components work together to form a secure DNS environment. The DNSKEY record contains the public key used for validating digital signatures, while the RRSIG record contains the actual digital signature. The DS record is used to establish a chain of trust between parent and child zones, and NSEC/NSEC3 records are utilized to prove the nonexistence of a domain name.

When it comes to how DNSSEC works, it’s all about the validation process and the chain of trust. When a DNS resolver receives a DNSSEC-protected response, it validates the digital signatures using the public keys provided in the DNSKEY records. This validation process establishes a chain of trust from the root of the DNS hierarchy down to the specific domain being queried, ensuring the data’s authenticity.

The benefits of using DNSSEC are significant, as it protects against cache poisoning and other types of attacks that can compromise the integrity of DNS data. By implementing DNSSEC, you can enhance the security and trust of your DNS infrastructure, providing a safer experience for your website visitors. However, it’s essential to recognize that DNSSEC is not a complete security solution and does come with certain limitations and challenges, such as increased complexity in DNS management. Despite these challenges, implementing DNSSEC is a crucial step in securing your online presence.

Setting Up DNSSEC (An Overview)

Before you set up DNSSEC, make sure you have a good understanding of DNS concepts and access to your DNS zone files. Additionally, you’ll need the appropriate tools and software to generate cryptographic keys, sign your DNS zone, and manage DNSSEC records.

First, you’ll need to generate two sets of cryptographic keys: the Key Signing Key (KSK) and the Zone Signing Key (ZSK). The KSK is used to sign the DNSKEY record, while the ZSK is used to sign other DNS records in your zone. By having separate keys for these purposes, you can maintain a higher level of security and control over your DNSSEC implementation.

Next, sign your DNS zone by creating RRSIG records for each DNS record in the zone using the ZSK. You’ll also need to create NSEC or NSEC3 records, which are used to prove the nonexistence of a domain name when a query returns a negative response. These records help prevent attackers from successfully forging a negative response for a legitimate domain.

Once you have signed your zone, publish the DNSKEY records, which include both the KSK and ZSK, in the DNS zone. It’s essential to verify the DNSKEY records to ensure they are accurate and working correctly. After publishing the DNSKEY records, generate and publish the DS records for your KSK. You’ll need to send these DS records to your domain’s parent zone (usually your domain registrar), which will publish them in their zone. This establishes a chain of trust between your domain and the parent domain. Make sure to verify the DS records with the parent zone to ensure they are correct and properly set up.

Lastly, configure your DNS resolver to validate DNSSEC by enabling DNSSEC validation in its settings. Once this is done, test the validation process to ensure everything is working correctly. By following these steps, you’ll have successfully set up DNSSEC for your domain, providing an additional layer of security to your DNS infrastructure.

Setting Up DNSSEC With BIND

To set up DNSSEC with BIND, follow these steps. Note that the commands and file paths provided may vary depending on your operating system and BIND installation:

Install BIND (If Not Already Installed)

For Debian/Ubuntu-based systems:

sudo apt-get update
sudo apt-get install bind9

For CentOS/RHEL-based systems:

sudo yum install bind bind-utils

Edit the named.conf.options file, usually located in /etc/bind/ or /etc/named.conf on CentOS/RHEL systems:

sudo nano /etc/bind/named.conf.options

Enable DNSSEC validation by adding the following lines within the ‘options’ block:

dnssec-enable yes;
dnssec-validation auto;

Save the file and restart BIND:

sudo systemctl restart bind9

Generate the KSK and ZSK

Navigate to the BIND keys directory, usually /etc/bind/keys/ or /etc/named/keys/ on CentOS/RHEL systems:

cd /etc/bind/keys/

Generate the KSK:

dnssec-keygen -a RSASHA256 -b 2048 -f KSK example.com

Generate the ZSK:

dnssec-keygen -a RSASHA256 -b 1024 example.com

Replace “example.com” with your domain name.

Sign the Zone

Create a file named “named.conf.keys” in the /etc/bind/ or /etc/ directory on CentOS/RHEL systems:

sudo nano /etc/bind/named.conf.keys

Add the contents of your KSK and ZSK .key files to the “named.conf.keys” file:

key "example.com.ksk" {
    algorithm RSASHA256;
    secret "KSK_BASE64_KEY";
};
key "example.com.zsk" {
    algorithm RSASHA256;
    secret "ZSK_BASE64_KEY";
};

Replace “KSK_BASE64_KEY” and “ZSK_BASE64_KEY” with the actual Base64 keys from your .key files.

Include “named.conf.keys” in your main BIND configuration file:

include "/etc/bind/named.conf.keys";

Edit your zone configuration in the named.conf.local file:

sudo nano /etc/bind/named.conf.local

Add the “auto-dnssec maintain;” and “inline-signing yes;” lines within the ‘zone’ block:

zone "example.com" {
    type master;
    file "/etc/bind/zones/db.example.com";
    auto-dnssec maintain;
    inline-signing yes;
    key-directory "/etc/bind/keys";
};

Save the file and reload BIND:

sudo systemctl reload bind9

Verify your DNSSEC Configuration

Use the “dig” command to check the DNSKEY and DS records:

dig +dnssec +multiline DNSKEY example.com
dig +dnssec +multiline DS example.com

Replace “example.com” with your domain name.

If everything is set up correctly, you should see the DNSKEY and RRSIG records in the output.

Remember that setting up DNSSEC with BIND is a complex process, and the commands provided may need to be adjusted depending on your specific system and configuration. Always consult BIND’s official documentation and seek help from the BIND community if you encounter issues or need clarification.

Maintaining DNSSEC

Maintaining DNSSEC is an ongoing process that requires diligence and adherence to best practices. One of the most critical aspects of DNSSEC maintenance is proper key management. Regular key rollovers are necessary to ensure the continued security of your DNSSEC implementation. There are two types of key rollovers you need to be aware of: ZSK rollovers and KSK rollovers. ZSK rollovers occur more frequently, typically every few months, while KSK rollovers are less frequent, usually every 1-2 years. Ensure that you follow the recommended timelines for key rollovers to minimize the risk of key compromise.

Another essential aspect of key management is the secure storage of your private keys. Protecting these keys from unauthorized access is crucial to maintaining the integrity of your DNSSEC implementation. Implement proper access controls and follow security best practices when handling your private keys.

Monitoring and troubleshooting your DNSSEC setup is also an important part of maintaining its effectiveness. Utilize DNSSEC validation tools to routinely check the status of your DNSSEC records and validation processes. Familiarize yourself with common issues that may arise, such as expired keys or incorrect DS records, and learn how to resolve these problems to keep your DNSSEC running smoothly.

Lastly, stay up-to-date with DNSSEC developments, including updates to standards and best practices. Participating in the DNSSEC community can help you stay informed about the latest advancements, as well as provide you with valuable resources and support when troubleshooting or optimizing your DNSSEC setup. By maintaining your DNSSEC implementation and staying current with the latest developments, you’ll continue to provide a secure and reliable DNS environment for your users.

Rekeying DNSSEC With BIND

Rekeying DNSSEC with BIND involves performing a key rollover for the Zone Signing Key (ZSK) and/or Key Signing Key (KSK). This process helps maintain the security of your DNSSEC implementation. Follow these steps to perform a key rollover with BIND:

Note: Replace “example.com” with your domain name in the commands below.

Navigate to the BIND keys directory, usually /etc/bind/keys/ or /etc/named/keys/ on CentOS/RHEL systems:

cd /etc/bind/keys/

Generate a new ZSK:

dnssec-keygen -a RSASHA256 -b 1024 -r /dev/urandom example.com

Update your zone configuration to include the new ZSK:

Edit the named.conf.keys file, usually located in /etc/bind/ or /etc/ directory on CentOS/RHEL systems:

sudo nano /etc/bind/named.conf.keys

Add the contents of the new ZSK .key file to the “named.conf.keys” file:

key "example.com.newzsk" {
    algorithm RSASHA256;
    secret "NEW_ZSK_BASE64_KEY";
};

Replace “NEW_ZSK_BASE64_KEY” with the actual Base64 key from your new ZSK .key file.

Edit your zone configuration in the named.conf.local file:

sudo nano /etc/bind/named.conf.local

Update the ‘zone’ block by adding a reference to the new ZSK:

zone "example.com" {
    ...
    key-directory "/etc/bind/keys";
    update-policy {
        grant example.com.newzsk zonesub ANY;
    };
};

Save the file and reload BIND:

sudo systemctl reload bind9

Initiate the ZSK rollover:

rndc loadkeys example.com

Verify that the new ZSK is being used:

dig +dnssec +multiline DNSKEY example.com

If the rollover was successful, you should see the new ZSK in the output.

Remove the old ZSK:

Once you are sure the new ZSK is in use, you can remove the old ZSK from the named.conf.keys file and delete the old ZSK .key and .private files from the keys directory.

For KSK rollover, the process is similar but requires coordination with your domain’s parent zone (usually your domain registrar). You will need to generate a new KSK, update your DS record at the parent zone, and then follow the steps above to complete the rollover. Make sure to consult BIND’s official documentation and seek help from the BIND community if you encounter issues or need clarification.

Conclusion

In conclusion, as you’ve learned throughout this guide, implementing DNSSEC is an essential step in enhancing the security and integrity of your DNS infrastructure. It’s crucial to remember that implementing DNSSEC is not a one-time task. Ongoing maintenance, monitoring, and staying up-to-date with the latest developments in the DNSSEC community are all essential aspects of ensuring the continued security and effectiveness of your DNSSEC implementation.

By following the steps outlined in this guide and committing to maintaining and improving your DNSSEC setup, you are taking a significant step towards securing your online presence. Your efforts in implementing and managing DNSSEC will contribute to a more secure and trustworthy internet for everyone.