How to Set Up a Raspberry Pi DNS Server?

A Domain Name System (DNS) server translates domain names that humans can easily remember to IP addresses that computers use to identify devices on a network. Setting up your own DNS server with a Raspberry Pi allows you to resolve domain names on your local network without relying on an external provider.

How to Set Up a Raspberry Pi DNS Server?

Why Set Up a Local DNS Server?

Here are some reasons you may want to set up a custom DNS server at home or for a small business:

  • Enhanced security and privacy – Using your own DNS server allows you to block access to unwanted or dangerous sites. It also prevents your browsing data from being collected by your internet service provider.
  • Faster performance – A local DNS cache speeds up domain name lookups by storing previously visited sites. This helps reduce latency when accessing frequently visited domains.
  • Custom domain routing – Define custom subnets and local domains that map to devices on your own network. This allows addressing local servers or IoT devices more easily.
  • Redundancy – Acts as a fallback DNS server if your ISP’s DNS fails or has connectivity issues.

Prerequisites

Before setting up a Raspberry Pi DNS server, you’ll need:

  • A Raspberry Pi computer. Any model should work though the newer RPi 4 is recommended.
  • Raspberry Pi OS installed. The default Raspbian operating system is ideal.
  • Ethernet cable for wired network connectivity.
  • A power adapter and microSD card.
  • (Optional) A secondary DNS server configured at your network level for redundancy.

Installation Steps

Follow these steps to get your Raspberry Pi set up as an internal DNS server:

1. Update the Operating System

Start by updating the OS packages:

sudo apt update

sudo apt full-upgrade

This ensures you have the latest security patches and software updates.

2. Install DNS Server Packages

Next install BIND (Berkley Internet Naming Daemon), a popular DNS software:

sudo apt install bind9 dnsutils

BIND handles DNS queries and resolutions on the Pi. The utilities provide tools like dig and host for testing lookups.

3. Configure the DNS Server

Edit the main BIND config file with sudo privileges:

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

Uncomment and modify the following lines:

forwarders {

  8.8.8.8;

  8.8.4.4;

listen-on port 53 { 127.0.0.1; };

listen-on-v6 port 53 { ::1; };  

allow-query { localhost; };

recursion yes;

dnssec-validation auto;

auth-nxdomain no; # conform to RFC1035

This configures the Pi to use Google’s public DNS servers for non-local lookups, while listening on the local interfaces for queries from our own network clients. Adjust IP addresses here if needed.

Warning: Use firewall policies like ufw to only allow connections from trusted sources.

4. Add Local Domains (Optional)

To define custom local domains, edit:

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

And add zones like:

zone “homelab. Local” {

        type master;

        file “/etc/bind/zones/db.homelab.local”;

zone “188.192.in-addr.arpa” {

        type master;

        file “/etc/bind/zones/db.192.168”;

This allows defining devices in these domains later. Save and exit the editor when done.

5. Create Zone Files

Next create your zone files that define subdomains.

sudo nano /etc/bind/zones/db.homelab.local

Add local host details:

; BIND reverse zone file for local routing

$TTL    604800

@       IN      SOA     dns.homelab.local. dns.homelab.local. 

                              3         ; Serial

                         604800         ; Refresh

                          86400         ; Retry

                        2419200         ; Expire

                         604800 )       ; Negative Cache TTL

; name servers

                NS      dns.homelab.local.

; PTR records

51             IN      PTR     nas.homelab.local.   ; NAS server

15             IN      PTR     access-point.homelab.local. ; WiFi AP

Save files when done adding hosts.

6. Restart DNS Service

Restart the service to load the new configuration:

sudo systemctl restart bind9

Check status with systemctl status bind9 to confirm startup was successful.

7. Configure DHCP Server

To direct clients like desktops and mobiles to use the Pi as their DNS provider, the DHCP daemon configuration needs adjusting on your router or Pi.

Edit dhcpcd config:

sudo nano /etc/dhcpcd.conf

And set the Pi’s IP as the DNS server:

static domain_name_servers=192.168.1.100

If running DHCP on Pi, edit dnsmasq instead:

sudo nano /etc/dnsmasq.conf

Set the router IP, gateway IP, and Pi’s IP for DNS:

interface=eth0     

dhcp-range=192.168.1.100,192.168.1.150,255.255.255.0,24h

dhcp-option=3,192.168.1.1

dhcp-option=6,192.168.1.1    

server=192.168.1.1

address=/homelab. Local/192.168.1.1          

server=/homelab. Local/192.168.1.100

Now restart networking or the DHCP service.

8. Update Client DNS Settings

On each client device, configure the Pi’s local IP as the custom DNS server under network settings. Alternatively, manually set DNS in dhcpcd config if using Linux.

After two minutes, local clients should now be using your Raspberry Pi BIND server for DNS!

Testing and Verification

Use dig and host for lookups:

host access-point.homelab.local

> access-point.homelab.local has address 192.168.1.15

dig nas.homelab.local

; <<>> DiG 9.16.1-Ubuntu <<>> nas.homelab.local

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64959

;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 65494

;; QUESTION SECTION:

;nas.homelab.local.     IN  A

;; ANSWER SECTION:

nas.homelab.local.  604800 IN A 192.168.1.51

You can also test sites like Facebook that should return public IPs:

dig facebook.com  

; <<>> DiG 9.16.1-Ubuntu <<>> facebook.com

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39178

;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

This validates that public DNS queries are working via the configured forwarders, while internal domains resolve locally.

Configuring Secondary DNS Server (Optional)

For redundancy, a secondary DNS server can be configured on your network router or another machine. Edit its DHCP daemon config to advertise itself as another nameserver to clients.

Edit the secondary server’s named.conf.options:

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

Comment out the forwarding line, and add your Pi DNS as master:

// forwarders { 8.8.8.8; 8.8.4.4; };

allow-transfer { 192.168.1.100; }; // Pi DNS IP

zone “homelab. Local” {

    type slave;

    masters { 192.168.1.100; }; // Pi DNS IP 

    file “/etc/bind/zones/db.homelab.local”;

};

This configures zone transfers from primary DNS. Restart the service to load it. Clients now have two redundant nameservers for failover.

Other Tips

  • Use a static IP for your Pi DNS server.
  • Configure the router DHCP lease time to match the BIND zone TTL.
  • Add firewall policies limiting TCP/UDP port 53 access to only your LAN.
  • Use Cloudflare or similar upstream resolvers for filtering and faster public DNS.

And that covers setting up a caching DNS resolver with blocklist filtering using a Raspberry Pi! With devices now resolving local domains and fall over DNS in place, you can start assigning friendly names for all your homelab or office devices.

Key Takeaways: How to Setup a Raspberry Pi DNS Server

  • Setting up a dedicated DNS server provides enhanced security, privacy and performance compared to relying on an ISP or public servers.
  • The most popular DNS server software for Raspberry Pi is BIND (Berkley Internet Naming Daemon) which is robust and customizable.
  • Configuring conditional forwarding allows resolving custom internal hostnames while sending external lookups to faster resolvers like Google or Cloudflare.
  • Using your router’s DHCP server makes it easy to distribute the Pi DNS address to all local network clients.
  • A secondary DNS server can provide redundancy in case the primary Pi fails or is unavailable.
  • Use firewall policies, encrypted DNS and access control to lock down the DNS server to protect from attacks.

Frequently Asked Questions

Q: Do I need a static IP Address for my Pi DNS Server?
A. Yes, your Pi should use a static IP set in its OS network config. This ensures clients can always resolve the server IP. Using DHCP reservations also works.

Q: Does the Pi need two network adapters for DNS duty?
A. No, the Pi only requires one Ethernet or WiFi network connection to operate as your DNS server. However adding a second adapter for management could be useful.

Q: What performance impact will the DNS server have on my Pi?
A. Running bind9 and caching local queries causes minimal load on modern Pis. For 100+ clients consider using a more powerful SBC or server.

Q: Can I encrypt DNS queries to the Pi using DNS over TLS/HTTPS?
A. Yes! Using forwarded DoT upstream resolvers and configuring BIND to listen on 853/443 ports allows securing your DNS traffic.

Q: How do I customize blocked domain filters using the Pi DNS?
A. Simply set up Pi-hole alongside BIND for its advanced filtering featureset. You can then selectively block ads, trackers and malicious sites.

Q: What are the most important BIND settings to configure?
A. Focus on forwarders, access control, recursion, listening ports, and defining internal domains. Running SELinux/AppArmor profiles for bind9 tightens security.

Q: Is there a web interface available for managing Pi DNS Server?
A. Yes, using existing tools like Webmin or Cockpit makes it easy to update configs and view query logs through a browser dashboard.

Q: Can I link multiple Pi DNS servers together for high availability?
A. Yes, enabling zone transfers between primary and secondary Pi DNS nodes allows automatic syncing of records. Keep their configs identical for failover.

Q: How do I troubleshoot connectivity issues or problems resolving certain domain queries?
A. Check the logging config and query journalctl logs for error output. Use commands like dig and host to verify failures querying specific records.

Q: What are best practices when it comes to TTL and DHCP lease times for DNS zones?
A. Set your DHCP leases to match the zone’s TTL like 24 or 48 hours. This ensures records are updated when IP addresses rotate.

Q: Is there a limit to how many clients a single Raspberry Pi DNS server can handle?
A. A RPi 4 can handle 150+ clients depending on complexity. Use forwarding upstream to optimize public queries while handling custom internal traffic.

Q: Can I resolve public domains without setting up Forwarders?
A. Yes, but the BIND process must recursively query root and TLD servers which adds latency. Forwarders is faster for most use cases.

Q: How do I customize wildcard domain forwarding based on domain keywords?
A. Leverage the domain-insecure and forwarding options in BIND config. This is useful for catching typos or unknown internal domains.

Q: What are the main security considerations for my DIY DNS server?
A. Use encrypted transfer protocols, restrict TCP/UDP port access, enable logging, monitor for DDoS attacks, update often, and consider using DNSSEC.

Q: Can Android and iOS mobile devices use the Pi DNS without any special VPN software?
A. Yes, simply configure the Pi’s IP address manually in the network or WiFi settings dropdown on any smartphone or tablet connected to your LAN.

Q: If my homelab VLAN lacks a router, can the Pi supply DHCP and DNS together?
A. Absolutely! Enable DHCP in dnsmasq and then link it to Pi DNS for a self-contained network services box. Adjust firewall rules accordingly.

Q: What is the best DNS benchmarking tool for testing cache performance?
A. Namebench and resperf are great DNS speed testing tools. Run them before and after to compare public DNS against your new Pi server.

Q: Can I use cloud hosted Raspberry Pis instead of my own hardware?
A. Yes, providers like Mythic Beasts offer hosted Pi plans for running your own BIND instances. This saves you from physical deployment.

Q: What is the difference between an authoritative and recursive DNS Server?
A. Authoritative servers only respond for zones they are configured for based on local records. Recursive servers query other nameservers to resolve unknown requests.

Q: Can I use a Raspberry Pi Zero for my DNS server?
A. The Pi Zero hardware can work but has limited processing power. For a few clients it may suffice, but for 20+ devices, using a Pi 3B+ or Pi 4 is recommended to prevent scaling issues. The Zero W can work over WiFi in very small deployments.

Q: How do I configure log rotation and monitoring for my Pi DNS server?
A. It’s important to enable logging in BIND and rotate logs regularly to prevent disk space issues. Set up logrotate to compress/delete logs older than 30 days. Monitor key metrics like memory usage, DNS queries per second, cache hit rate, and latency with solutions like Grafana or Netdata. Logging and monitoring helps troubleshoot problems early.

Conclusion

Configuring Raspberry Pi as your own recursive DNS server provides increased privacy, speed, redundancy and customizability compared to relying solely on your ISP. With affordable SBC hardware and freely available software like BIND, setting up local domain resolution is within reach of any homelab or small business user.

By tweaking the forwarding, listen address, access control, and defining custom zones, you can tailor the DNS experience to suit your specific local requirements. Mixing conditional upstream resolution with internal domains gives you the best of both worlds.

While DNS seems trivial, its importance for linking hostnames and IPs together cannot be overstated. By running your own dns server with RPi you take back control while enabling exciting functionality like wildcard routing for your lab.

So consider deploying a DIY DNS resolver using these steps next time you deploy or reorganize your virtualization cluster, home automation systems, or IoT networks that could benefit from local DNS flexibility.

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