Random IPv4 Generator

IPv4 number generator in depth

An IPv4 address is a 32-bit identifier traditionally written as four decimal octets separated by dots — dotted-decimal notation — where each octet ranges from 0 to 255. That gives a total of 2³² ≈ 4.29 billion possible addresses. The pool sounds large, but the central IANA pool was officially exhausted on 3 February 2011 and the five Regional Internet Registries (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC) ran out between 2015 and 2020. The transition to IPv6 (128 bits, 2¹²⁸ addresses) has been under way ever since.

Classes (historical) and modern CIDR

The original IPv4 design split the space into classes by the leading bits, deprecated in 1993 in favour of CIDR (Classless Inter-Domain Routing). The mnemonic still helps:

• Class A — 1.0.0.0/8 to 126.0.0.0/8
• Class B — first octet 128-191
• Class C — first octet 192-223
• Class D — multicast, 224.0.0.0-239.255.255.255
• Class E — reserved, 240.0.0.0-255.255.255.255

Reserved ranges

• RFC 1918 private: 10.0.0.0/8 (24 host bits), 172.16.0.0/12 (20), 192.168.0.0/16 (16)
• Loopback: 127.0.0.0/8 — typically 127.0.0.1 (localhost)
• Link-local / APIPA: 169.254.0.0/16 (Windows self-assigns when DHCP fails)
• Multicast: 224.0.0.0/4
• Default route / unspecified: 0.0.0.0/8
• CGNAT: 100.64.0.0/10 — carrier-grade NAT, used by ISPs to share scarce public IPv4 among many subscribers

CIDR, subnet masks and NAT

CIDR notation writes a prefix length after the address: 192.168.1.0/24 means the first 24 bits are network and the last 8 are host — i.e. 256 addresses with subnet mask 255.255.255.0. Common sizes:

• /30 — 4 addresses (2 usable), classic point-to-point link
• /24 — 256 addresses, the typical home LAN
• /16 — 65,536 addresses, a midsize corporate site

Subnetting divides a block into smaller ones — a /24 can become four /26s of 64 hosts each. NAT (Network Address Translation) lets one public IPv4 serve an entire LAN, translating ports on the fly; it is the reason IPv4 limps along despite the exhaustion.

FAQ

Are the generated IPs routable? Yes — with "public only" enabled, the tool filters out the reserved ranges above and emits IPs that could be assigned somewhere on the internet. With it off, you may get private or loopback IPs too.

Is this good for testing? Excellent: seed firewall rules, log parsers, geo-IP fixtures, anomaly-detection trainers and CIDR-validation libraries. The output is random mock data, not a list of real hosts.

Can I use a generated IP as my own? No. Your computer's IPv4 is assigned by your ISP (public) or your router via DHCP (private). Hard-coding a random address breaks routing immediately.

Will IPv6 replace IPv4? Slowly. As of 2026 IPv6 carries roughly 45% of internet traffic and is the only realistic path forward, but legacy IPv4 hangs on thanks to NAT, CGNAT and an active market for transferred address blocks priced at $30-60 per IP.