Random IP Address Generator

What this tool does

Random IP Address Generator creates any number of plausible IPv4 and/or IPv6 addresses for testing, documentation and sample data. Restrict output to private-range addresses (RFC 1918 for IPv4, unique local addresses for IPv6), to addresses that look public by excluding reserved, loopback, link-local and multicast blocks, or generate freely from the entire address space. A CIDR-aware mode fills in random host bits within a specific network you supply, such as 10.20.0.0/16 or 2001:db8::/48, so the results always belong to that block.

Testing network configuration tools, filling sample rows in a log viewer, or writing documentation about subnetting often calls for IP addresses that are not tied to any real device. Picking plausible values by hand is slow, and getting RFC 1918 private ranges or IPv6 unique local addresses exactly right without a reference is easy to get wrong.

This generator produces IPv4 and/or IPv6 addresses on demand, with presets for private-only and public-looking addresses, plus a CIDR-aware mode that keeps every generated address inside a specific network block you provide.

How to use Random IP Address Generator

1. Set how many addresses to generate, from 1 up to 1000.
2. Choose the address family: IPv4, IPv6, or Both to mix the two.
3. Pick a range: Any for unrestricted addresses, Private only for RFC 1918 (IPv4) or unique local (IPv6) ranges, or Public-looking only to exclude reserved, loopback, link-local and multicast blocks.
4. Alternatively, turn on "Generate inside a CIDR block" and enter a network such as 10.20.0.0/16 or 2001:db8::/48; every generated address will keep that block's network bits and randomise only the host bits.
5. Press Generate to produce the batch, then copy individual addresses or the whole list with one click.

Tips for better results

• Use "Private only" when you need addresses that look like they belong to a home or office LAN, such as for a network-diagram mockup.
• CIDR mode is the most precise option: give it the exact subnet your test fixtures should live in and every address will land inside it, including correctly randomised host bits for partial-byte prefixes like /12 or /20.
• "Public-looking only" is a best-effort filter, not a guarantee the address is actually routable or assigned; it simply excludes the well-known reserved, private, loopback, link-local and multicast blocks.
• Choose "Both" for address family when you want a realistic mixed-protocol log or dataset rather than a single-family list.

Common use cases

• Populating sample rows in a log viewer, firewall rule tester, or network dashboard mockup with non-identifying addresses.
• Generating private LAN addresses for a subnetting tutorial or network diagram.
• Producing addresses confined to a specific CIDR block for integration tests against a mocked IP range.
• Creating randomized fixture data for an application that stores or displays client IP addresses.

Common mistakes to avoid

• Assuming "Public-looking only" addresses are guaranteed to be assigned and reachable on the internet; the filter only removes known reserved and private blocks, it does not check real-world allocation.
• Entering a CIDR block with the wrong prefix length for the intended address family, such as /48 on an IPv4 address; IPv4 prefixes must be 0-32 and IPv6 prefixes 0-128.
• Forgetting that a /32 (IPv4) or /128 (IPv6) CIDR has zero host bits, so every generated address in that mode will be identical to the block itself.
• Using randomly generated addresses as if they were safe to publish as real contact or server information; treat them purely as test or placeholder data.