What is the Random IP Address Generator?
Public IPv4 results skip reserved ranges such as 10.0.0.0/8, 127.0.0.0/8, 169.254.0.0/16 and documentation blocks. Private results use the RFC 1918 ranges (10.x, 172.16–31.x, 192.168.x). IPv6 public addresses fall in the global unicast 2000::/3 space and private ones in the fd00::/8 unique-local range.
An IPv4 address is 32 bits written as four decimal numbers from 0 to 255; IPv6 uses 128 bits written as eight groups of four hexadecimal digits, where one run of all-zero groups can be shortened to “::”. CIDR notation such as 192.168.1.0/24 gives a network address followed by the number of fixed leading bits — a /24 leaves 8 bits for hosts, or 256 addresses. These basics make it much easier to read firewall rules, routing tables and the logs you fill with generated addresses.
How to use the Random IP Address Generator
- Adjust the options above to match what you need.
- Press Generate (or hit Enter / Space) to create fresh results instantly.
- Click any result to copy it, or use Copy all.
- Download everything as CSV, JSON or TXT, or share a link with your settings.
Popular uses
- Log & SIEM testing — synthetic traffic with realistic source IPs.
- Firewall rules — test allow/deny lists and CIDR matching.
- Network training — practice subnetting with fresh examples.
Why use RandNow?
- Instant & unlimited — no sign-up, no daily caps.
- Private by design — results are generated in your browser, not on our servers.
- Export-ready — copy, CSV, JSON and TXT downloads built in.
- Cryptographically random — powered by the Web Crypto API.
Subnetting practice with random addresses
Generate a private IPv4 address, pick a prefix length and work out the network address, the broadcast address and the usable host range. For 192.168.37.140/26 the block size is 64, so the network is 192.168.37.128, the broadcast is 192.168.37.191 and usable hosts run from .129 to .190. Repeat with fresh addresses and different prefixes until the pattern becomes second nature. As a shortcut, the block size equals 256 minus the value of the last non-zero octet in the subnet mask: a /26 has the mask 255.255.255.192, and 256 minus 192 gives 64. With practice you can work out most subnets in your head, which is a big help in exams and when troubleshooting a real network.
Documentation ranges and responsible use
RFC 5737 reserves 192.0.2.0/24, 198.51.100.0/24 and 203.0.113.0/24 for examples, and RFC 3849 reserves 2001:db8::/32 for IPv6 documentation. Use those in manuals and screenshots, and keep generated public addresses inside test systems. Never scan, probe or attack an address you don’t own or have permission to test. Press Generate to create a fresh set for your next lab.
Frequently asked questions
Are these IPs in use?
Public results may be assigned to real organisations. Don’t scan or attack them — use them only as test data.
What are private IP addresses?
Ranges reserved for local networks that aren’t routed on the internet: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.
Can I generate IPv6?
Yes, switch Version to IPv6.
What does /24 mean after an IP address?
It is CIDR notation: the first 24 bits identify the network and the remaining 8 bits identify hosts, giving 256 addresses in the block.
Which IP addresses should I use in documentation?
Use the ranges reserved for examples: 192.0.2.0/24, 198.51.100.0/24 and 203.0.113.0/24 for IPv4, and 2001:db8::/32 for IPv6.