IPv6 /56 Subnet
A common assignment to home and small business customers: 256 /64 networks. Enter any address below to see its /56 block.
- Free
- No Sign-Up
- Runs in Your Browser
Examples:
IPv6 network
256 /64 networks
Documentation
Details
First Address
Last Address
Total Addresses
/64 Networks
Expanded
Address Entered
Split Into Subnets
2001:db8:abcd::/572001:db8:abcd:: – 2001:db8:abcd:7f:ffff:ffff:ffff:ffff
2001:db8:abcd:80::/572001:db8:abcd:80:: – 2001:db8:abcd:ff:ffff:ffff:ffff:ffff
Subnet Calculator
IPv6 /56 at a glance
Prefix/56
Total Addresses2^72
/64 Networks256
/56 Customers1
Host Bits72
Hex Digits Fixed14
An IPv6 /56 fixes the first 56 of 128 bits. That is exactly 14 hex digits, so the boundary falls cleanly between digits, which makes addresses easy to read.
IPv6 has no broadcast address, so every address in the block can be used, but networks with hosts on them should be /64 so SLAAC and neighbour discovery work as designed.
Questions
How many /64s are in a /56?
256.
How many addresses are in an IPv6 /56?
2^72 (4.72 × 10^21).
What size IPv6 block should a hosting provider give each VM?
A /64 per VM is the cleanest: the customer can use any addresses inside it, and abuse handling and reverse DNS work per /64. A single /128 also works but some software expects a /64.
Free Tools
More tools
Subnet CalculatorNetwork, broadcast, usable range and mask for any IPv4 or IPv6 CIDR.Bandwidth CalculatorConvert Mbps to TB per month, and time a transfer at any speed.MTU & MSS CalculatorWork out MTU and TCP MSS through VLANs, PPPoE, VXLAN and VPN tunnels.What Is My IPYour public IP address, reverse DNS, network and ASN.
Every address on your network, watched
Frabs maps each IP to the VM that owns it and stops the abuse coming from it, on Proxmox, Virtualizor, VirtFusion and SolusVM.