What is DNSSEC?
Domain Name System Security Extensions (DNSSEC) adds security to DNS by enabling cryptographic verification of DNS responses, protecting against cache poisoning and other attacks.
Authentication
DNSSEC uses digital signatures to authenticate DNS responses, ensuring the data comes from the authoritative source and hasn't been tampered with.
Data Integrity
Cryptographic hashes protect DNS data from modification in transit, maintaining the integrity of your DNS records.
Chain of Trust
DNSSEC establishes a hierarchical chain of trust from the root zone down to your domain, providing end-to-end verification.
labx.dnssecsd.org using the
name server nsx.pi.sd.
BIND9 Installation & Configuration
Setting up a secure DNS server with proper logging and zone configuration.
Install BIND9
Update your system and install the necessary DNS server packages.
sudo apt-get update
sudo apt-get install bind9 bind9utils dnsutilsConfigure BIND9 Options
Edit the main configuration file to set up listening addresses and security settings.
sudo vim /etc/bind/named.conf.options
# Configuration options:
options {
listen-on { 127.0.0.1; x.x.x.x; };
zone-statistics yes;
version none;
hostname none;
allow-transfer { none; };
auth-nxdomain no;
recursion no;
};recursion no and
allow-transfer { none; } enhances
security by preventing unauthorized zone
transfers and recursive queries.
Enable and Start BIND9
Enable the service for automatic startup and verify it's running correctly.
Service Management Commands:
-
sudo systemctl enable named- Enable auto-start -
sudo systemctl restart named- Restart the service -
sudo systemctl status named- Check service status -
sudo netstat -putan | grep 53- Verify DNS is listening
Configure Logging (Optional)
Set up comprehensive logging for monitoring and troubleshooting.
sudo mkdir /var/cache/bind/log
sudo chown -R bind:bind /var/cache/bind/log
sudo vim /etc/bind/named.conf.logLogging Configuration Content (/etc/bind/named.conf.log):
Include the logging configuration in your main config:
sudo vim /etc/bind/named.conf
# Add this line:
include "/etc/bind/named.conf.log";• Query Log: Records all DNS queries (5 versions kept)
• Transfer Log: Tracks zone transfers (10 versions kept)
• DNSSEC Log: Detailed DNSSEC signing and validation events
• Update Log: Dynamic DNS update operations
• Debug/Info Logs: General server operations and debugging
Zone Configuration
Creating and configuring the DNS zone for your domain.
Create Zone Directory and File
sudo mkdir /var/cache/bind/master
sudo vim /var/cache/bind/master/db.labx.dnssecsd.orgZone File Content:
Configure Zone in BIND
sudo chown -R bind:bind /var/cache/bind/
sudo vim /etc/bind/named.conf.local
# Add zone configuration:
zone "labx.dnssecsd.org." {
type master;
file "master/db.labx.dnssecsd.org";
masterfile-format text;
};Test Zone Configuration
Restart BIND and test your zone configuration with DNS queries.
Testing Commands:
-
sudo systemctl restart named- Restart BIND -
dig @localhost labx.dnssecsd.org- Test A record -
dig @localhost labx.dnssecsd.org aaaa- Test AAAA record -
dig @localhost labx.dnssecsd.org soa- Test SOA record -
dig @localhost labx.dnssecsd.org mx- Test MX record
DNSSEC Zone Signing
Generate cryptographic keys and sign your DNS zone for enhanced security.
Generate DNSSEC Keys
Create both Zone Signing Key (ZSK) and Key Signing Key (KSK) pairs.
sudo mkdir /var/cache/bind/keys
cd /var/cache/bind/keys
# Generate Zone Signing Key (ZSK)
sudo dnssec-keygen -3 -a ECDSAP256SHA256 labx.dnssecsd.org
# Generate Key Signing Key (KSK)
sudo dnssec-keygen -f KSK -3 -a ECDSAP256SHA256 labx.dnssecsd.org
sudo chown -R bind:bind /var/cache/bind/keys•
-3 enables NSEC3 for enhanced
security•
-f KSK designates the Key Signing
Key•
ECDSAP256SHA256 uses elliptic
curve cryptography
Configure Automatic Signing
Update the zone configuration to enable automatic DNSSEC maintenance.
sudo vim /etc/bind/named.conf.local
# Updated zone configuration:
zone "labx.dnssecsd.org." {
type master;
file "master/db.labx.dnssecsd.org";
masterfile-format text;
auto-dnssec maintain;
inline-signing yes;
key-directory "/var/cache/bind/keys";
};•
auto-dnssec maintain - Automatic
key management and signing•
inline-signing yes - Keeps
unsigned and signed versions separate•
key-directory - Specifies where
DNSSEC keys are stored
Activate DNSSEC Signing
Reload the configuration and verify DNSSEC records are generated.
Verification Commands:
-
sudo rndc reload- Reload BIND configuration -
dig @localhost dnskey labx.dnssecsd.org- View DNSKEY records -
dig @localhost +dnssec +multiline labx.dnssecsd.org any- View all DNSSEC records
Generate DS Record
Create the DS (Delegation Signer) record for the parent zone.
cd /var/cache/bind/keys
sudo dnssec-dsfromkey <KSK.key public key>
# Example output:
labx.dnssecsd.org. IN DS 19670 13 2 4F5A5C5BB25D4EA2D946EDC62918A91CFAE76BA15C12B80DF377841A1D705FB9DNSSEC Verification
Validate your DNSSEC implementation and monitor its status.
Command Line Verification
Use dig commands to verify DNSSEC records and signatures are properly configured.
-
dig @a.mail.sd +dnssec labx.dnssecsd.org. DS -
dig +dnssec +multiline labx.dnssecsd.org
Online DNSSEC Tools
Use web-based tools to validate your DNSSEC implementation and visualize the chain of trust.
Monitoring
Regular monitoring ensures your DNSSEC implementation remains functional and secure over time.
- Monitor key expiration dates
- Check DS record in parent zone
- Validate DNSSEC chain periodically
DNSViz Visualization
Visual representation of the DNSSEC chain of trust for labx.dnssecsd.org
DNSViz analysis showing the complete DNSSEC validation path from root to labx.dnssecsd.org
• Green boxes: Validated DNSSEC signatures
• Lines and arrows: Show the delegation path from root zone
• Key symbols: Represent DNSKEY and DS records
• Complete chain: Indicates successful DNSSEC implementation