Random IP Address Generator (IPv4 & IPv6)

Random IP addresses are handy for test data, log samples, firewall rule tests, load-testing scripts and documentation. This generator makes up to 1,000 IPv4 or IPv6 addresses at once. It can keep to public space, skipping private networks, loopback, link-local, carrier-grade NAT, documentation blocks and the other IANA special-purpose ranges. It can also stay inside a range you give, such as 10.0.0.0/8 for an internal lab, with no duplicates and an optional random port.

How to use this tool

1. Choose IPv4 or IPv6 and how many addresses you need.
2. Optionally enter a CIDR range; leave it empty for the whole address space.
3. Keep "public only" for realistic internet addresses, or untick it to allow private and reserved ones.
4. Choose duplicates, sorting and a port range, then press Calculate and copy the list.

Formula

address = network + random(0 … 2^(32 − prefix) − 1) for IPv4, or network | random host bits for IPv6

Small ranges (up to 65,536 addresses) are listed first and drawn without replacement, so "no duplicates" is exact and a /30 never yields more than its addresses. Large ranges draw random host bits and discard special-purpose or repeated values. Public IPv6 addresses come from 2000::/3, the global unicast block.

Example

With the range 10.0.0.0/30 and network/broadcast skipped, only 10.0.0.1 and 10.0.0.2 are left, so asking for two unique addresses always returns those two, and asking for ten is refused. With no range and "public only", an IPv4 list never contains 10.x, 172.16–31.x, 192.168.x, 127.x or 169.254.x addresses.