How to Change DNS Settings in Linux

Recommended DNS Servers

TorGuard DNS (VPN Users Only)

Public DNS Servers

Check Your Current DNS Configuration

First, identify which DNS management system your Linux uses:

# Check if using systemd-resolved
systemctl status systemd-resolved

# Check current DNS servers
resolvectl status  # For systemd
nmcli dev show | grep DNS  # For NetworkManager
cat /etc/resolv.conf  # Traditional method

Method 1: systemd-resolved (Ubuntu 18.04+, Fedora, Arch)

Option A: Using resolvectl (Recommended)

# Set DNS for specific interface
sudo resolvectl dns eth0 1.1.1.1 1.0.0.1

# Set DNS for all interfaces
sudo resolvectl dns 1.1.1.1 1.0.0.1

# Enable DNS over TLS
sudo resolvectl dnsovertls yes

# Make changes persistent
sudo systemctl restart systemd-resolved

Option B: Edit Configuration File

# Edit systemd-resolved configuration
sudo nano /etc/systemd/resolved.conf

# Add/modify these lines:
[Resolve]
DNS=1.1.1.1 1.0.0.1
FallbackDNS=9.9.9.9 149.112.112.112
DNSOverTLS=yes
DNSSEC=yes
DNSStubListener=yes

# Apply changes
sudo systemctl restart systemd-resolved

Option C: Using systemd-networkd

# Create network configuration
sudo nano /etc/systemd/network/20-wired.network

# Add content:
[Match]
Name=eth0

[Network]
DHCP=yes
DNS=1.1.1.1
DNS=1.0.0.1

# Enable and restart
sudo systemctl enable systemd-networkd
sudo systemctl restart systemd-networkd

Method 2: NetworkManager (GNOME, KDE)

GUI Method

1. Open Network Settings (varies by desktop)
2. Click gear icon next to your connection
3. Go to IPv4/IPv6 tab
4. Set DNS to "Manual" or "Automatic, addresses only"
5. Enter DNS servers: 1.1.1.1, 1.0.0.1
6. Apply changes

Command Line Method

# List connections
nmcli connection show

# Modify connection (replace 'Wired connection 1' with your connection name)
nmcli connection modify "Wired connection 1" ipv4.dns "1.1.1.1 1.0.0.1"
nmcli connection modify "Wired connection 1" ipv4.ignore-auto-dns yes

# For IPv6
nmcli connection modify "Wired connection 1" ipv6.dns "2606:4700:4700::1111 2606:4700:4700::1001"

# Apply changes
nmcli connection up "Wired connection 1"

Method 3: resolvconf (Traditional Debian/Ubuntu)

# Install resolvconf if needed
sudo apt-get install resolvconf

# Edit base configuration
sudo nano /etc/resolvconf/resolv.conf.d/base

# Add DNS servers:
nameserver 1.1.1.1
nameserver 1.0.0.1
options edns0 trust-ad

# Update configuration
sudo resolvconf -u

# Make persistent across reboots
sudo systemctl enable resolvconf.service

Method 4: Direct /etc/resolv.conf Edit

# Backup current configuration
sudo cp /etc/resolv.conf /etc/resolv.conf.backup

# Edit resolv.conf
sudo nano /etc/resolv.conf

# Add DNS servers:
nameserver 1.1.1.1
nameserver 1.0.0.1
options edns0

# Prevent overwriting (varies by system)
sudo chattr +i /etc/resolv.conf  # Make immutable
# To undo: sudo chattr -i /etc/resolv.conf

Distribution-Specific Methods

Ubuntu 22.04+ (Netplan)

# Edit netplan configuration
sudo nano /etc/netplan/01-netcfg.yaml

# Example configuration:
network:
  version: 2
  renderer: NetworkManager
  ethernets:
    eth0:
      dhcp4: true
      nameservers:
        addresses: [1.1.1.1, 1.0.0.1]

# Apply changes
sudo netplan apply

Fedora/RHEL/CentOS

# Using nmcli (preferred)
nmcli con mod "System eth0" ipv4.dns "1.1.1.1 1.0.0.1"
nmcli con up "System eth0"

# Or edit interface configuration
sudo nano /etc/sysconfig/network-scripts/ifcfg-eth0
# Add: DNS1=1.1.1.1
#      DNS2=1.0.0.1

Arch Linux

# Using systemd-resolved (recommended)
sudo systemctl enable systemd-resolved
sudo ln -sf /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf

# Or using dhcpcd
echo "static domain_name_servers=1.1.1.1 1.0.0.1" | sudo tee -a /etc/dhcpcd.conf
sudo systemctl restart dhcpcd

OpenSUSE

# Using YaST (GUI)
sudo yast2 dns

# Or edit config
sudo nano /etc/sysconfig/network/config
# Set: NETCONFIG_DNS_STATIC_SERVERS="1.1.1.1 1.0.0.1"

Configure DNS over HTTPS (DoH)

Using cloudflared

# Install cloudflared
wget https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-linux-amd64
sudo mv cloudflared-linux-amd64 /usr/local/bin/cloudflared
sudo chmod +x /usr/local/bin/cloudflared

# Create systemd service
sudo cloudflared service install

# Configure
sudo nano /etc/cloudflared/config.yml
# Add:
proxy-dns: true
proxy-dns-upstream:
  - https://1.1.1.1/dns-query
  - https://1.0.0.1/dns-query

# Start service
sudo systemctl start cloudflared
sudo systemctl enable cloudflared

# Point system DNS to cloudflared
# Add to your DNS configuration: 127.0.0.1

Verify DNS Configuration

Test DNS Resolution

# Using dig
dig @1.1.1.1 google.com

# Using nslookup
nslookup google.com

# Using systemd-resolve
resolvectl query google.com

# Check which DNS server is being used
dig +short whoami.akamai.net @resolver1.opendns.com

Check for DNS Leaks

# Command line test
curl https://dnsleaktest.com/api/v1/leak-test

# Or visit in browser
firefox https://torguard.net/dns-leak-test.php

Troubleshooting Common Issues

DNS Not Resolving

# Flush DNS cache
sudo systemctl restart systemd-resolved
# Or
sudo systemd-resolve --flush-caches

# Test connectivity
ping -c 4 1.1.1.1

# Check service status
systemctl status systemd-resolved
journalctl -u systemd-resolved

Changes Revert After Reboot

• Check if NetworkManager is overriding settings
• Ensure resolvconf service is enabled
• Verify no DHCP client is overwriting DNS
• Check for immutable flag on resolv.conf

Slow DNS Resolution

# Test DNS response time
time dig google.com @1.1.1.1
time dig google.com @8.8.8.8

# Use fastest responding server
# Add to resolv.conf:
options timeout:1 attempts:1 rotate

VPN and DNS Considerations

Prevent DNS Leaks with VPN

# For OpenVPN, add to .ovpn file:
dhcp-option DNS 10.8.0.1
dhcp-option DNS 10.10.0.1
block-outside-dns

# For WireGuard, add to .conf:
DNS = 10.8.0.1, 10.10.0.1

DNS Security Hardening

Enable DNSSEC

# For systemd-resolved
sudo nano /etc/systemd/resolved.conf
# Set: DNSSEC=yes

# Verify DNSSEC
dig +dnssec example.com

Use DNS over TLS

# systemd-resolved (Ubuntu 20.04+)
sudo resolvectl dnsovertls yes

# Stubby alternative
sudo apt install stubby
sudo systemctl enable stubby

Automation Scripts

Quick DNS Switcher

#!/bin/bash
# Save as ~/bin/dns-switch.sh

case "$1" in
    cloudflare)
        sudo resolvectl dns 1.1.1.1 1.0.0.1
        echo "Switched to Cloudflare DNS"
        ;;
    google)
        sudo resolvectl dns 8.8.8.8 8.8.4.4
        echo "Switched to Google DNS"
        ;;
    torguard)
        sudo resolvectl dns 10.8.0.1 10.10.0.1
        echo "Switched to TorGuard DNS"
        ;;
    *)
        echo "Usage: $0 {cloudflare|google|torguard}"
        ;;
esac