Mastering DNS Privacy: Pi-hole + Unbound + VPN Integration (bonus).

yannick Coffi -


Pi-hole + Unbound + OpenVPN creates a robust privacy-focused network by blocking ads, trackers, and malicious domains while preventing ISP snooping, DNS hijacking, and censorship. Unlike third-party resolvers such as Google DNS, Cloudflare, or ISP-provided DNS, Unbound operates recursively for complete independence and security. OpenVPN encrypts all traffic, shielding online activity from prying eyes and securing connections on public networks. With DNSSEC validation, intelligent caching, and a private VPN tunnel, browsing becomes faster, safer, and free from manipulation—delivering seamless, encrypted, and reliable connectivity. 🚀

For an in-depth look at DNS privacy and network security, check out our tutorial on Mastering DNS Privacy: Pi-hole + Unbound (Part 1 & Part 2). This powerful combination enhances your privacy, security, and control over DNS queries, ensuring a more secure and censorship-resistant browsing experience.


Integrating Pi-hole with OpenVPN


Integrating Pi-hole with OpenVPN allows you to filter DNS queries for all connected clients, enhancing privacy and security. To achieve this, you need to configure OpenVPN to push Pi-hole as the designated DNS server. This ensures that all VPN clients route their DNS requests through Pi-hole, even when they are connected remotely.

Edit OpenVPN server configuration:

$ sudo nano /etc/openvpn/server.conf

add

push "dhcp-option DNS 192.168.1.x"

This tells the clients to use the specified IP (192.168.1.x) as their DNS server.
Replace 192.168.1.x with your Pi-hole IP address!

add the following block for maximum privacy and security:

push "redirect-gateway def1"

This directive ensures that all client internet traffic, including web browsing, DNS queries, and other network requests, is securely tunneled through the VPN, preventing data leaks and masking the client's real IP address. When combined with Pi-hole as the DNS server, all DNS queries are filtered and resolved through Pi-hole, providing network-wide ad blocking, enhanced privacy, and greater control over your internet traffic.

However, this setting comes with some drawbacks:

• Routes all traffic, including local network, internet, and DHCP requests, through the VPN tunnel.
• Prevents clients from accessing local network resources (e.g., printers, file shares) unless explicitly allowed through custom routing rules.
• This may disrupt DHCP renewals since DHCP traffic is also routed through the VPN, preventing the client from communicating with the local DHCP server to obtain or renew its IP address.

Use this setting if you need a full-tunnel VPN for privacy and security, DO NOT require local network access, and want all DNS requests to be processed through Pi-hole for ad-blocking and tracking prevention.

or add the following block for Balanced Privacy and Functionality:

 push "redirect-gateway def1 bypass-dhcp"


This setting works the same as "redirect-gateway def1" but excludes DHCP traffic from being routed through the VPN, allowing clients to renew their DHCP lease from their home router. DNS queries are still routed through Pi-hole, ensuring ad-blocking and privacy, while local network resources like printers and NAS remain accessible. Additionally, local network speeds are faster since only internet traffic is tunneled through the VPN.


Use this setting if you want a full-tunnel VPN while maintaining local network access and avoiding DHCP lease issues when connecting from different networks. Still, it forces all internet traffic through the VPN, but DHCP requests stay local.


Now; if you only want local network access and don't want to route all internet traffic through the VPN, remove redirect-gateway and just use:

$ push "route 192.168.1.0 255.255.255.0"


For hybrid behavior:

$ push "redirect-gateway def1 bypass-dhcp bypass-dns"
$ push "route 192.168.1.0 255.255.255.0"

This encrypts all internet traffic through the VPN for privacy while allowing access to local network resources like printers and NAS, and ensuring DHCP renewals work without issues.


Restart OpenVPN and check its status:

$ sudo systemctl restart openvpn@server
$ sudo systemctl status openvpn@server


Use sudo systemctl restart openvpn@server when you need to apply changes or fix issues on your specific VPN server. This will reconnect all clients with the updated settings.



⚠️ Recommendation 💄

When integrating Pi-hole with OpenVPN, it's important to harden security and properly configure DNS settings.

Here are #3 of our best recommended practices:


1. Secure DNS Handling (Avoid Leaks)
Do not push external DNS servers to clients to ensure all DNS queries go through Pi-hole.

Comment out or remove:

#push "dhcp-option DNS 8.8.8.8"
#push "dhcp-option DNS 1.1.1.1"

Instead, explicitly set Pi-hole as the DNS server for connected VPN clients as stated above!

push "dhcp-option DNS 192.168.1.x"  # Assuming Pi-hole is running on the VPN server

2. Harden OpenVPN Security
Use Strong Encryption:

tls-version-min 1.2  # Enforces a minimum TLS version of 1.2 for security.
tls-cipher TLS-DHE-RSA-WITH-AES-256-GCM-SHA384  # Specifies a secure cipher suite for TLS handshake.
cipher AES-256-GCM  # Uses AES-256-GCM for strong encryption and authenticated encryption.
auth SHA512  # Ensures message integrity using SHA-512 hashing algorithm.
ncp-disable  # Disables Negotiable Cryptographic Parameters (NCP) to prevent weak cipher negotiation.


Enable Perfect Forward Secrecy (PFS)
Ensure you're using Elliptic Curve Diffie-Hellman (ECDH) instead of traditional DH:

dh none # Use ECDH instead of traditional DH
ecdh-curve secp384r1  # Uses the secp384r1 elliptic curve for Diffie-Hellman key exchange.


3. Disable IPv6 (Prevent IPv6 DNS Leaks)
If your network doesn't use IPv6, disable it in Pi-hole:


Pi-hole (/etc/pihole/pihole-FTL.conf)

Add this line:

AAAA_QUERY_ANALYSIS=no

Restart the DNS resolution service:

$ sudo systemctl restart pihole-FTL


Integrating Pi-hole with OpenVPN enforces network-wide ad blocking and secure DNS resolution. Using push dhcp-option DNS <Pi-hole-IP>, OpenVPN routes all DNS queries through Pi-hole, preventing leaks and enhancing privacy. Paired with Unbound, it eliminates reliance on third-party DNS providers, ensuring greater security and control. Regular blocklist updates maintain protection, making this setup a powerful solution for a private and ad-free network.

We hope you found these insights useful!