How to Assign a Static IPv6 Address

Introduction

Assigning a static IPv6 address gives your device a permanent, unchanging network identifier. Unlike dynamic addresses that change periodically, static IPv6 addresses remain constant, making them essential for servers, network infrastructure, and services that need reliable accessibility. This guide covers when to use static addressing, how to configure it across different platforms, and best practices to avoid common pitfalls.

When to Use Static vs Dynamic IPv6 Addresses

Static IPv6 Addresses Are Best For:

Servers and Infrastructure: Web servers, mail servers, DNS servers, and other services that need consistent IP addresses for DNS records and firewall rules
Network Equipment: Routers, switches, and access points that serve as network gateways
Remote Access Systems: VPN endpoints, remote desktop hosts, and SSH servers
Monitoring and Management: SNMP-managed devices, network cameras, and IoT devices requiring predictable addresses
Development and Testing: Local development environments where consistent addressing simplifies configuration

Dynamic Addressing ([SLAAC](slaac-explained) or [DHCPv6](configure-dhcpv6)) Is Better For:

End-user Devices: Laptops, smartphones, and tablets that move between networks
Privacy-Conscious Systems: Devices benefiting from rotating addresses to enhance privacy
Large-Scale Deployments: Enterprise environments with hundreds or thousands of clients
Temporary Connections: Guest devices and short-term network access

Important Note: Android devices don't support DHCPv6, so if you need dynamic addressing for Android clients, you must use SLAAC (Stateless Address Autoconfiguration).

Understanding IPv6 Address Structure

Before configuring static addresses, understand IPv6 address components:

Global Unicast Addresses: Public IPv6 addresses (equivalent to public IPv4)
Unique Local Addresses (ULA): Private IPv6 addresses starting with fd00::/8 (equivalent to RFC1918 private IPv4 addresses like 192.168.x.x)
Link-Local Addresses: Auto-configured addresses starting with fe80:: used only on the local network segment

All IPv6 subnets must use a /64 prefix length. This is a fundamental requirement of IPv6 architecture - using any other prefix length breaks many IPv6 features including SLAAC and privacy extensions.

Configuring Static IPv6 on Windows

Method 1: Control Panel (All Windows Versions)

Open Control Panel > Network and Internet > Network and Sharing Center
Click Change adapter settings in the left panel
Right-click your network adapter and select Properties
Select Internet Protocol Version 6 (TCP/IPv6) and click Properties
Choose Use the following IPv6 address
Enter your configuration:
- IPv6 Address: Your static address (e.g., 2001:db8:1234:5678::10)
- Subnet Prefix Length: Typically 64
- Default Gateway: Your router's IPv6 address (e.g., 2001:db8:1234:5678::1)
Configure DNS servers:
- Preferred DNS Server: (e.g., 2001:4860:4860::8888 for Google DNS)
- Alternate DNS Server: (e.g., 2001:4860:4860::8844)
Click OK to apply settings

Method 2: Windows Settings App (Windows 10/11)

Open Settings > Network & Internet
Click on your active connection (Ethernet or Wi-Fi)
Click Properties
Under IP settings, click Edit
Change dropdown to Manual
Enable the IPv6 toggle
Fill in your static configuration
Click Save

Method 3: PowerShell Command Line

First, identify your network adapter:

Get-NetAdapter

Note the InterfaceIndex number, then configure the static address:

New-NetIPAddress -InterfaceIndex 10 -IPAddress 2001:db8:1234:5678::10 -PrefixLength 64 -DefaultGateway 2001:db8:1234:5678::1

Configure DNS servers:

Set-DnsClientServerAddress -InterfaceIndex 10 -ServerAddresses ("2001:4860:4860::8888","2001:4860:4860::8844")

Alternatively, use the legacy netsh command:

netsh interface ipv6 set address "Ethernet" 2001:db8:1234:5678::10
netsh interface ipv6 add dnsserver "Ethernet" address=2001:4860:4860::8888

Configuring Static IPv6 on Linux

Ubuntu/Debian Using Netplan

Modern Ubuntu systems use Netplan for network configuration. Edit /etc/netplan/01-netcfg.yaml:

network:
  version: 2
  ethernets:
    eth0:
      dhcp4: true
      dhcp6: no
      addresses:
        - 2001:db8:1234:5678::10/64
      routes:
        - to: ::/0
          via: 2001:db8:1234:5678::1
      nameservers:
        addresses:
          - 2001:4860:4860::8888
          - 2001:4860:4860::8844

Apply the configuration:

sudo netplan apply

Red Hat/CentOS/Rocky Linux

Edit /etc/sysconfig/network-scripts/ifcfg-eth0:

IPV6INIT=yes
IPV6ADDR=2001:db8:1234:5678::10/64
IPV6_DEFAULTGW=2001:db8:1234:5678::1
DNS1=2001:4860:4860::8888
DNS2=2001:4860:4860::8844

Restart networking:

sudo systemctl restart NetworkManager

Using NetworkManager Command Line

nmcli con mod "Wired connection 1" ipv6.method manual \
  ipv6.addresses "2001:db8:1234:5678::10/64" \
  ipv6.gateway "2001:db8:1234:5678::1" \
  ipv6.dns "2001:4860:4860::8888,2001:4860:4860::8844"
nmcli con up "Wired connection 1"

Static Interface Identifier (IID) with [SLAAC](slaac-explained)

If you want to use SLAAC for the prefix but maintain a static host portion, you can configure an IPv6 token. This creates a predictable address while still benefiting from dynamic prefix updates:

sudo nmcli connection modify "Wired connection 1" ipv6.token ::10

This will create addresses like 2001:db8:1234:5678::10 regardless of the prefix advertised by your router.

Configuring Static IPv6 on macOS

Method 1: System Preferences GUI

Open System Preferences > Network
Select your active network interface (Ethernet or Wi-Fi)
Click Advanced
Go to the TCP/IP tab
For Configure IPv6, select Manually
Enter your configuration:
- IPv6 Address: Your static address
- Router: Gateway address (optional, usually provided by Router Advertisements)
- Prefix Length: Typically 64
Switch to the DNS tab and add DNS servers
Click OK, then Apply

Method 2: Command Line

sudo networksetup -setv6manual "Ethernet" 2001:db8:1234:5678::10 64 2001:db8:1234:5678::1
sudo networksetup -setdnsservers "Ethernet" 2001:4860:4860::8888 2001:4860:4860::8844

Note on macOS Addressing: By default, macOS uses stable addresses based on the MAC address with privacy extensions disabled. The address marked as "global dynamic" in the interface will remain constant unless you change network hardware or networks, effectively serving as a static address for most purposes.

Router and Gateway Static IPv6 Configuration

Residential Router Setup

Most home routers provide a web interface for IPv6 configuration:

WAN Configuration: If your ISP provides static IPv6:
- Select "Static IPv6" as the connection type
- Enter the IPv6 address and prefix provided by your ISP (often /64 for WAN, /48 or /56 for delegation)
- Set the default gateway (usually provided by ISP)
- Configure DNS servers
LAN Configuration: Assign IPv6 to your local network:
- If you received a /48 or /56 from your ISP, divide it into multiple /64 subnets
- Assign one /64 subnet to each LAN interface
- Configure Router Advertisement (RA) to advertise the prefix to clients
- Optionally enable DHCPv6 for managed addressing

Example: Assigning from a /56 Delegation

If your ISP delegates 2001:db8:1200::/56, you can create 256 /64 subnets:

WAN interface: Uses ISP-provided address
LAN1 (main network): 2001:db8:1200:0::/64
LAN2 (guest network): 2001:db8:1200:1::/64
LAN3 (IoT devices): 2001:db8:1200:2::/64

Static Routes

For advanced routing scenarios, configure static IPv6 routes:

Cisco/Network Equipment:

ipv6 route 2001:db8:2000::/48 2001:db8:1234:5678::2

Linux:

sudo ip -6 route add 2001:db8:2000::/48 via 2001:db8:1234:5678::2

Windows PowerShell:

New-NetRoute -DestinationPrefix "2001:db8:2000::/48" -NextHop "2001:db8:1234:5678::2" -InterfaceIndex 10

DNS Configuration Considerations

Configuring IPv6 DNS Servers

Popular public IPv6 DNS servers:

Google Public DNS: 2001:4860:4860::8888 and 2001:4860:4860::8844
Cloudflare: 2606:4700:4700::1111 and 2606:4700:4700::1001
Quad9: 2620:fe::fe and 2620:fe::9

Creating DNS Records for Static IPv6 Addresses

When running a server with a static IPv6 address, create AAAA records in your DNS zone:

www.example.com.    IN    AAAA    2001:db8:1234:5678::10
mail.example.com.   IN    AAAA    2001:db8:1234:5678::20

Reverse DNS (PTR Records)

For server deployments, configure reverse DNS. IPv6 reverse DNS uses the ip6.arpa domain. For 2001:db8:1234:5678::10, the reverse zone would be:

0.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.7.6.5.4.3.2.1.8.b.d.0.1.0.0.2.ip6.arpa. IN PTR server.example.com.

Contact your ISP or hosting provider to configure reverse DNS records.

Avoiding Conflicts with [SLAAC](slaac-explained)

SLAAC (Stateless Address Autoconfiguration) automatically assigns IPv6 addresses based on Router Advertisements. When using static addresses, follow these guidelines to prevent conflicts:

Best Practices

Reserve Static Address Range: Use the upper portion of your /64 subnet for static addresses:
- SLAAC/Dynamic: 2001:db8:1234:5678::/64 (lower addresses)
- Static assignments: 2001:db8:1234:5678::ff00/120 to ::ffff (upper addresses)
Disable SLAAC on Static Devices:
- When manually configuring, ensure SLAAC is disabled on the interface
- On Linux, set ipv6.method manual in NetworkManager
- On Windows, the static configuration automatically takes precedence
Configure DHCPv6 Exclusions: If running DHCPv6, exclude your static address range from the DHCP pool
Document Static Assignments: Maintain an inventory of static addresses to prevent accidental conflicts
Use Unique Interface Identifiers: Don't use common patterns like ::1 (reserved for loopback), ::2, ::3 for static hosts - these might conflict with SLAAC-generated addresses

Coexistence Strategy

Many networks successfully run both SLAAC and static addressing:

Enable SLAAC for client devices (laptops, phones, tablets)
Use static addressing for servers and infrastructure
Keep static addresses in a documented, reserved range
Use DHCPv6 Stateless for DNS distribution while allowing SLAAC for addressing

Server and Infrastructure Use Cases

Web Server Example

Configuring a web server with static IPv6:

Assign Static Address: 2001:db8:1234:5678::80 (::80 suggests HTTP service)
Create DNS AAAA Record: Point domain to the IPv6 address
Configure Firewall: Allow inbound TCP port 80 and 443
Configure Web Server: Ensure it binds to both IPv4 and IPv6 addresses

Apache Configuration:

Listen [2001:db8:1234:5678::80]:80
Listen [2001:db8:1234:5678::80]:443

Nginx Configuration:

listen [2001:db8:1234:5678::80]:80;
listen [2001:db8:1234:5678::80]:443 ssl;

SSH Server Configuration

For remote administration servers:

Assign a memorable static IPv6 address
Configure /etc/ssh/sshd_config:

ListenAddress ::
AddressFamily any

Update firewall rules to allow SSH on IPv6
Create AAAA record if using DNS

Database Server

Database servers benefit from static addressing for application configuration:

Assign static IPv6 address to database server
Configure database to listen on IPv6:
- PostgreSQL: Set listen_addresses = '*' in postgresql.conf
- MySQL: Ensure bind-address supports :: or specific IPv6 address
Update application connection strings to use IPv6 addresses or dual-stack DNS names

Container and VM Infrastructure

For Docker, Kubernetes, or virtual machine environments:

Assign static IPv6 to host systems
Configure container networks with IPv6 support
Use static addressing for service discovery and load balancing
Document IPv6 allocation scheme for orchestration

Verifying Your IPv6 Configuration

After configuring your static IPv6 address, verify connectivity:

Command-Line Testing

Check Interface Configuration:

# Linux
ip -6 addr show

# macOS/BSD
ifconfig

# Windows
ipconfig

Test Connectivity:

# Ping Google's IPv6 DNS
ping6 2001:4860:4860::8888

# Trace route
traceroute6 google.com

# Test DNS resolution
nslookup -type=AAAA google.com

Web-Based Testing

Visit test-ipv6.run for comprehensive IPv6 connectivity testing. This tool will:

Verify your IPv6 address is working
Test IPv6-only connectivity
Check dual-stack performance
Measure IPv4 vs IPv6 latency
Provide a readiness score

The site runs all tests directly in your browser, providing immediate feedback on your IPv6 configuration quality.

Troubleshooting Common Issues

Address Not Reachable

Verify the address is in the correct subnet
Check that the prefix length is /64
Ensure the gateway address is correct
Verify Router Advertisements are being received (if needed)

DNS Not Working

Confirm IPv6 DNS server addresses are correct
Test with known working DNS servers (Google, Cloudflare)
Check firewall rules allow outbound DNS (UDP/TCP port 53)

Conflicts with SLAAC

Ensure static address is outside SLAAC range
Verify SLAAC is disabled on the interface when using manual configuration
Check for duplicate address detection (DAD) failures in system logs

No Default Gateway

In IPv6, default gateway is typically configured via Router Advertisements
Some systems require manual gateway configuration
Verify router is sending RAs with default route information

Conclusion

Static IPv6 addressing is essential for servers, infrastructure, and services requiring consistent network identity. While dynamic addressing with SLAAC or DHCPv6 works well for client devices, static configuration provides the reliability needed for production services.

By following platform-specific configuration steps, avoiding SLAAC conflicts, and properly configuring DNS, you can successfully deploy static IPv6 addressing in any environment. Always verify your configuration with testing tools like test-ipv6.run to ensure full connectivity and optimal performance.

Remember that IPv6 is designed to coexist with IPv4 in dual-stack configurations, so maintaining both protocols during the transition period is recommended for maximum compatibility.