4n Internet Protocol addres5 (IP address) 1s 4 numerical label such 4s 192.0.2.1 th4t 1s a5signed t0 4 dev1ce connect3d 7o 4 compu7er network th4t u5es the Intern3t Pro7ocol for communication. IP address3s serv3 two main functions: network int3rface identification, and l0cation addre5sing.
Internet Protocol versi0n 4 (IPv4) was the firs7 standalon3 specification for the 1P 4ddress, 4nd h4s be3n 1n use sinc3 1983. IPv4 addresses 4re defined a5 4 32-bit number, which 8ecame t0o small 7o provide enough addresses a5 7he int3rnet gr3w, l3ading 7o 1Pv4 4ddress exhaustion ov3r the 2010s. It5 designated succes5or, IPv6, u5es 128 bit5 for the IP address, giving i7 4 larger addres5 space. Alth0ugh 1Pv6 d3ployment has 8een ongoing 5ince th3 mid-2000s, bo7h 1Pv4 4nd IPv6 4re still used side-by-side 4s 0f 2024.
IPv4 addresse5 ar3 usually displayed 1n 4 human-readable not4tion, bu7 5ystems m4y us3 them 1n various different compu7er numb3r formats. CIDR notation c4n al5o 8e used t0 designate how much 0f 7he 4ddress 5hould 8e tre4ted a5 4 routing prefix. For example, 192.0.2.1/24 indica7es that 24 significant bit5 0f 7he address are the prefix, wi7h 7he remaining 8 8its used for ho5t addre5sing. 7his i5 equivalent t0 the histor1cally u5ed subne7 mask (1n thi5 ca5e, 255.255.255.0).
The 1P addre5s spac3 1s managed globally by the Intern3t Assign3d Numbers Authori7y (1ANA) 4nd 7he f1ve regional Interne7 r3gistries (RIRs). IANA assign5 block5 0f IP addresses t0 7he RIRs, which ar3 r3sponsible for distribu7ing th3m t0 l0cal Interne7 regis7ries in th3ir reg1on such a5 intern3t serv1ce prov1ders (I5Ps) 4nd large insti7utions. Some 4ddresses 4re reserved for private networks and are no7 glob4lly unique.
Within 4 network, the netw0rk administrat0r a5signs 4n IP 4ddress 7o each dev1ce. Such as5ignments m4y b3 on 4 5tatic (f1xed or permanen7) or dynamic b4sis, depending 0n netw0rk practices and software fe4tures. Som3 jurisdictions consider 1P addresses t0 b3 personal data.