Improving Security with Secure DNS Solutions

The Domain Name System (DNS) is a fundamental part of internet infrastructure, translating human-readable domain names into IP addresses. When a user enters a website address, their browser queries a DNS server to retrieve the corresponding IP. However, this process is often unencrypted, exposing users to surveillance, censorship, and potential manipulation.

By default, DNS queries are transmitted in plaintext, making them visible to internet service providers (ISPs), governments, and malicious actors. This lack of encryption allows for tracking user activity and even redirecting users to malicious websites through DNS spoofing attacks. Governments also use DNS filtering to block access to certain websites, as seen in many cases of internet censorship.

Common DNS Security Threats

1. DNS Hijacking – Attackers intercept and modify DNS responses, redirecting users to fraudulent sites.
2. Man-in-the-Middle Attacks – Unencrypted DNS queries can be intercepted, allowing for data manipulation.
3. DNS Spoofing – Also known as cache poisoning, this attack inserts false DNS records to redirect traffic.
4. Data Privacy Concerns – Many public DNS providers log user activity, which can be sold or shared with third parties.

Securing DNS Traffic

Several protocols and tools have been developed to mitigate these security risks and enhance privacy:

1. DNSSEC (Domain Name System Security Extensions)

DNSSEC ensures DNS responses are authentic by digitally signing DNS records. This prevents cache poisoning attacks but does not encrypt queries, leaving privacy concerns unaddressed.

2. DNSCrypt

DNSCrypt encrypts DNS queries, preventing ISPs and attackers from monitoring or tampering with requests. However, DNSCrypt is not widely adopted as an internet standard and is gradually being phased out in favor of other solutions.

3. DNS over TLS (DoT)

DoT secures DNS queries by encapsulating them in a TLS-encrypted tunnel (port 853). This prevents eavesdropping but can still be detected and blocked by ISPs employing deep packet inspection (DPI).

4. DNS over HTTPS (DoH)

DoH encrypts DNS queries using HTTPS (port 443), making them indistinguishable from regular web traffic. This allows users to bypass censorship and ISP tracking effectively.

Implementing Secure DNS Solutions

To improve privacy and security, users can configure their devices to use encrypted DNS resolvers. One effective approach is deploying a DNS proxy to forward queries securely:

Using DNS Proxy with DoH/DoT

Run the proxy using a secure DNS resolver:

./dnsproxy -u https://dns.cloudflare.com/dns-query

Clone and build DNS Proxy:

git clone https://github.com/AdguardTeam/dnsproxy.git
cd dnsproxy
go build

Install Go (if not installed):

sudo apt-get update && sudo apt-get -y upgrade
wget https://dl.google.com/go/go1.13.3.linux-amd64.tar.gz
sudo tar -xvf go1.13.3.linux-amd64.tar.gz
sudo mv go /usr/local
export GOROOT=/usr/local/go
export GOPATH=$HOME/Projects/Proj1
export PATH=$GOPATH/bin:$GOROOT/bin:$PATH

Self-Hosting a DNS Server

Public DNS services like Google DNS (8.8.8.8) and Cloudflare DNS (1.1.1.1) claim not to log user data, but trusting third parties is always a risk. The best approach for privacy-conscious users is to host their own DNS resolver:

• Pi-hole – A network-wide ad blocker that also acts as a customizable DNS server.
• Unbound – A validating, recursive, caching DNS resolver that supports DoT and DoH.

Conclusion

Securing DNS is crucial for maintaining online privacy and integrity. By adopting encrypted DNS solutions such as DoT and DoH, users can prevent data interception and bypass censorship. Implementing self-hosted DNS resolvers further ensures control over DNS queries, eliminating reliance on third-party providers. As internet threats evolve, securing DNS will remain a vital component of a robust cybersecurity strategy.