IPv6 ULA Generator

Generate RFC4193 IPv6 Unique Local Address prefixes and /64 subnets in your browser.

ULA options

Leave the Global ID blank for a random RFC4193 prefix, or enter a known 40-bit ID to recreate a plan.

Use exactly 10 hexadecimal characters, such as a1b2c3d4e5, or leave blank for a random value.

Choose 1 to 50 subnets to list under the generated /48 prefix.

Use 1 to 4 hexadecimal digits. 0000 starts at the first subnet.

Generated ULA

Use the /48 prefix for your site and assign the /64 subnets to individual network segments.

/48 prefix fd00:0000:0000::/48
Global ID 0000000000

Prefix details

Network ID
fd00:0000:0000
Listed subnets
4


                        
                        


                        

                            
                            
                            
                        

                    

                

            


            

                
When to use the IPv6 ULA Generator

                
Common ways to plan private IPv6 networks with this generator:

                
    
                    
  • Create a private site prefix
    Generate an RFC4193 /48 prefix for labs, offices, or home networks without requesting public IPv6 space.
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  • Plan routed /64 segments
    List consecutive /64 subnets for VLANs, VPNs, containers, and test environments.
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  • Validate an existing Global ID
    Enter a known 10-character Global ID to rebuild the same prefix and check the subnet range.
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  • Share network designs
    Copy the prefix, copy the subnet list, or export JSON for tickets, runbooks, and documentation.
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  • Work from mobile
    Generate and copy ULA plans from a phone or tablet during field setup or troubleshooting.
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IPv6 ULA Generator FAQ

                

                    

                        
How do I use this app?

                        
Choose a subnet count and starting subnet ID, then generate a random ULA or enter a 10-character Global ID to recreate a known prefix.

                    

                    

                        
Is this app free to use?

                        
Yes. The IPv6 ULA Generator is free and does not require an account.

                    

                    

                        
What happens to my input data?

                        
All generation and validation run in your browser. The app does not store or send your Global ID or generated subnets.

                    

                    

                        
Why am I getting an error or unexpected output?

                        
Check that the Global ID has exactly 10 hexadecimal characters, the subnet count is between 1 and 50, and the requested range does not pass ffff.

                    

                    

                        
Where can I find instructions and troubleshooting tips?

                        
Use the in-app Help panel. It explains the inputs, RFC4193-oriented tips, copy actions, and keyboard-friendly controls.