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DNS security refers to the protection of the Domain Name System (DNS) from cyber threats, such as hacking, phishing, and malware. DNS is a critical component of the internet infrastructure, responsible for translating domain names into IP addresses. DNS security is essential to prevent cyber attacks that can compromise the integrity, confidentiality, and availability of online services.
You Should Know:
1. DNSSEC (Domain Name System Security Extensions)
DNSSEC uses cryptographic signatures to ensure the authenticity and integrity of DNS data. To enable DNSSEC on a Linux server, use the following commands:
sudo apt-get install bind9 sudo named-checkconf sudo rndc reconfig sudo rndc reload
Verify DNSSEC with:
dig +dnssec example.com
2. DNS Firewall
A DNS firewall can be implemented using tools like `iptables` to block malicious DNS requests:
sudo iptables -A INPUT -p udp --dport 53 -j DROP sudo iptables -A INPUT -p tcp --dport 53 -j DROP
To allow only trusted DNS servers:
sudo iptables -A INPUT -p udp --dport 53 -s trusted_dns_ip -j ACCEPT
3. DNS Encryption (DoH/DoT)
Configure DNS over HTTPS (DoH) or DNS over TLS (DoT) on Linux using cloudflared:
sudo apt-get install cloudflared sudo cloudflared proxy-dns --port 5053
Update `/etc/resolv.conf` to use the local proxy:
nameserver 127.0.0.1 options edns0
4. DNS Filtering
Use `Pi-hole` for DNS filtering to block malicious domains:
curl -sSL https://install.pi-hole.net | bash
Configure it to block phishing and malware sites by updating blocklists in the Pi-hole admin interface.
5. DNS Anycast
Implement DNS anycast using BIND9 on multiple servers:
sudo apt-get install bind9 sudo nano /etc/bind/named.conf.options
Add the following configuration:
options {
anycast;
};
6. DNS Redundancy
Set up secondary DNS servers for redundancy:
sudo nano /etc/bind/named.conf.local
Add the following:
zone "example.com" {
type slave;
file "/var/lib/bind/db.example.com";
masters { primary_dns_ip; };
};
7. DNS Monitoring
Use `dnstop` to monitor DNS traffic:
sudo apt-get install dnstop sudo dnstop -l enp0s3
For real-time monitoring, use `tshark`:
sudo tshark -i enp0s3 -f "port 53"
8. DNS Auditing
Audit DNS logs using `logwatch`:
sudo apt-get install logwatch sudo logwatch --detail high --service named
Analyze DNS queries with:
sudo cat /var/log/named/queries.log
What Undercode Say:
DNS security is a critical aspect of cybersecurity, ensuring the integrity, confidentiality, and availability of online services. By implementing DNSSEC, DNS firewalls, encryption, and monitoring tools, organizations can protect their DNS infrastructure from cyber threats. Regular auditing and redundancy further enhance security, making DNS a robust component of your IT infrastructure.
For further reading:
References:
Reported By: Ahmed Bawkar – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
