List of assigned /8 IPv4 address blocks
Some large blocks of IPv4 addresses, the former Class A network blocks, are assigned in whole to single organizations or related groups of organizations, either by the Internet Corporation for Assigned Names and Numbers, through the Internet Assigned Numbers Authority, or a regional Internet registry.
Each block contains 256 = 2 = 16,777,216 addresses, which covers the whole range of the last three delimited segments of an IP address. This means that 256 /8 address blocks fit into the entire IPv4 space.
As IPv4 address exhaustion has advanced to its final stages, some organizations, such as Stanford University, formerly using, have returned their allocated blocks to assist in the delay of the exhaustion date.
List of reserved /8 blocks
| Block | Organization | IANA date | RIR date | Notes |
| 0.0.0.0/8 | IANALocal Identification | 1981-09 | Originally IANAReserved 1981-09. 0.0.0.0/8 reserved for self-identification. | |
| 10.0.0.0/8 | IANAPrivate Use | 1995-06 | Reserved for Private Networks. Formerly ARPANET. | |
| 127.0.0.0/8 | IANALoopback | 1981-09 | 127.0.0.0/8 is reserved for loopback. | |
| 224.0.0.0/8–239.0.0.0/8 | Multicast | 1981-09 | 1991-05-22 | Multicast registered in |
| 240.0.0.0/8–255.0.0.0/8 | Future Use | 1981-09 | Reserved for future use. 255.255.255.255 is reserved for "limited broadcast" destination address. |
List of /8 blocks assigned to the regional Internet registries
The regional Internet registries allocate IPs within a particular region of the world.| Block | Organization | IANA date | RIR date | Notes |
| 1.0.0.0/8 | APNIC | 2010-01 | Formerly IANAreserved 1981-09. | |
| 2.0.0.0/8 | RIPE NCC | 2009-10 | Formerly IANAreserved 1981-09. | |
| 3.0.0.0/8 | ARIN | 1994-05 | Amazon.com. Formerly General Electric Company. | |
| 4.0.0.0/8 | ARIN | 1992-12 | Various registries. Formerly Bolt Beranek and Newman Inc., then GTE, then Genuity, then Level 3 Communications, Inc. | |
| 5.0.0.0/8 | RIPE NCC | 2010-11 | Formerly IANAreserved 1995-07. | |
| 8.0.0.0/8 | ARIN | 1992-12 | 1992-12-01 | Various registries. Formerly Bolt Beranek and Newman Inc., then GTE, then Genuity, then Level 3 Communications, Inc. |
| 9.0.0.0/8 | ARIN | 1992-08 | IBM except for 9.9.9.0/24, which is Quad9. | |
| 13.0.0.0/8 | ARIN | 1991-09 | Various registries. Formerly Xerox. | |
| 14.0.0.0/8 | APNIC | 2010-04 | Starting 1991-06-01, was used to map Public Data Network addresses to IP addresses. Returned to IANA 2008-01-22. This network was reclaimed by IANA in 2007 and was subsequently re-allocated in 2010. See RFC 877 and RFC 1356 for historical information. | |
| 15.0.0.0/8 | ARIN | 1991-09 | Various registries. Formerly Hewlett-Packard Company. HP Inc still uses a portion of the block. | |
| 16.0.0.0/8 | ARIN | 1994-11 | 1989-05-18 | Various registries. Formerly Digital Equipment Corporation, then Compaq, then Hewlett-Packard. |
| 18.0.0.0/8 | ARIN | 1994-01 | Various registries. Formerly MIT. | |
| 20.0.0.0/8 | ARIN | 1994-10 | Various registries. Formerly DXC Technology. Computer Sciences Corporation, who owned this block, merged with HP Enterprise Services to create DXC Technology on 3 April 2017. | |
| 23.0.0.0/8 | ARIN | 2010-11 | Formerly IANAreserved 1995-07. | |
| 24.0.0.0/8 | ARIN | 2001-05 | 2001-05-01 | Formerly IANACable Block 1995-07, then ARINCable Block 2001-05. Updated to ARIN not before 2007. |
| 25.0.0.0/8 | RIPE NCC | 1995-01 | As of 2005-08-23 entire block assigned to UK Ministry of Defence | |
| 27.0.0.0/8 | APNIC | 2010-01 | Formerly IANAreserved 1995-04. | |
| 31.0.0.0/8 | RIPE NCC | 2010-05 | 2010-05-18 | Formerly IANAreserved 1991-04. |
| 32.0.0.0/8 | ARIN | 1994-06 | Various registries. Formerly AT&T Global Network Services. Originally Norsk Informasjonsteknologi. IBM acquired Norsk Informasjonsteknologi in 1995. | |
| 34.0.0.0/8 | ARIN | 1993-03 | Various registries. Formerly Halliburton Company. | |
| 35.0.0.0/8 | ARIN | 1994-04 | 2012-08 | Various registries. Formerly Merit Network 1986. |
| 36.0.0.0/8 | APNIC | 2010-10 | Formerly Stanford University 1993-04, then IANAReserved 2000-07. | |
| 37.0.0.0/8 | RIPE NCC | 2010-11 | Formerly IANAReserved 1995-04. | |
| 39.0.0.0/8 | APNIC | 2011-01 | Formerly IANAReserved 1995-04. | |
| 40.0.0.0/8 | ARIN | 1994-06 | Various registries. | |
| 41.0.0.0/8 | AFRINIC | 2005-04 | Formerly IANAReserved 1995-05. | |
| 42.0.0.0/8 | APNIC | 2010-10 | Formerly IANAReserved 1995-07. | |
| 43.0.0.0/8 | APNIC | 1991-01 | 1989-02-21 | Various registries. Originally Japan Inet 1991-01 or 1989-02-21. Administered by APNIC not before 2007. |
| 44.0.0.0/8 | ARIN | 1992-07 | 2019-07-18 | Various registries. Originally Amateur Radio Digital Communications. was sold to Amazon on 2019-07-18. |
| 45.0.0.0/8 | ARIN | 1995-01 | 1991-09-09 | Various registries. Formerly Interop Show Network 1995-01 or 1991-09-09. Returned to ARIN in 2010-10 except a /15 block. In 2011 it became available for distribution. |
| 46.0.0.0/8 | RIPE NCC | 2009-09 | Formerly Bolt Beranek and Newman Inc. 1992-12. Returned to IANA in 2007-04. Updated to IANAReserved in 2007-04. | |
| 47.0.0.0/8 | ARIN | 1991-01 | Various registries. Formerly Bell-Northern Research, which became Northern Telecom, aka, Nortel, until its demise, circa 2010. | |
| 48.0.0.0/8 | ARIN | 2023-10-02 | 1990-12-07 | Assignment administered by ARIN. Formerly Prudential Financial, who still use a portion of the space. |
| 49.0.0.0/8 | APNIC | 2010-08 | Formerly Joint Technical Command 1994-05. Updated to IANAReserved in 2007-05. | |
| 50.0.0.0/8 | ARIN | 2010-02 | Formerly Joint Technical Command 1994-05. Updated to IANAReserved in 2007-05. | |
| 51.0.0.0/8 | RIPE NCC | 1994-08 | Various registries. Formerly UK Government Department for Work and Pensions. | |
| 52.0.0.0/8 | ARIN | 1991-12 | Formerly DuPont. | |
| 54.0.0.0/8 | ARIN | 1992-03 | Various registries. | |
| 56.0.0.0/8 | ARIN | 1992-11 | Formerly United States Postal Service. | |
| 57.0.0.0/8 | RIPE NCC | 1995-05 | Formerly SITA. | |
| 58.0.0.0/8 | APNIC | 2004-04 | ||
| 59.0.0.0/8 | APNIC | 2004-04 | ||
| 60.0.0.0/8 | APNIC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 61.0.0.0/8 | APNIC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 62.0.0.0/8 | RIPE NCC | 1997-04 | ||
| 63.0.0.0/8 | ARIN | 1997-04 | ||
| 64.0.0.0/8 | ARIN | 1999-07 | ||
| 65.0.0.0/8 | ARIN | 2000-07 | ||
| 66.0.0.0/8 | ARIN | 2000-07 | ||
| 67.0.0.0/8 | ARIN | 2001-05 | ||
| 68.0.0.0/8 | ARIN | 2001-06 | ||
| 69.0.0.0/8 | ARIN | 2002-08 | ||
| 70.0.0.0/8 | ARIN | 2004-01 | ||
| 71.0.0.0/8 | ARIN | 2004-08 | ||
| 72.0.0.0/8 | ARIN | 2004-08 | ||
| 74.0.0.0/8 | ARIN | 2005-06 | ||
| 75.0.0.0/8 | ARIN | 2005-06 | ||
| 76.0.0.0/8 | ARIN | 2005-06 | ||
| 77.0.0.0/8 | RIPE NCC | 2006-08 | ||
| 78.0.0.0/8 | RIPE NCC | 2006-08 | ||
| 79.0.0.0/8 | RIPE NCC | 2006-08 | ||
| 80.0.0.0/8 | RIPE NCC | 2001-04 | ||
| 81.0.0.0/8 | RIPE NCC | 2001-04 | ||
| 82.0.0.0/8 | RIPE NCC | 2002-11 | ||
| 83.0.0.0/8 | RIPE NCC | 2003-11 | ||
| 84.0.0.0/8 | RIPE NCC | 2003-11 | ||
| 85.0.0.0/8 | RIPE NCC | 2004-04 | ||
| 86.0.0.0/8 | RIPE NCC | 2004-04 | ||
| 87.0.0.0/8 | RIPE NCC | 2004-04 | ||
| 88.0.0.0/8 | RIPE NCC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 89.0.0.0/8 | RIPE NCC | 2005-06 | ||
| 90.0.0.0/8 | RIPE NCC | 2005-06 | Except for 90.0.0.0/9, which is Orange | |
| 91.0.0.0/8 | RIPE NCC | 2005-06 | ||
| 92.0.0.0/8 | RIPE NCC | 2007-03 | ||
| 93.0.0.0/8 | ARIN | 1994-05 | ||
| 94.0.0.0/8 | RIPE NCC | 2007-07 | ||
| 95.0.0.0/8 | RIPE NCC | 2007-07 | ||
| 96.0.0.0/8 | ARIN | 2006-10 | ||
| 97.0.0.0/8 | ARIN | 2006-10 | ||
| 98.0.0.0/8 | ARIN | 2006-10 | ||
| 99.0.0.0/8 | ARIN | 2006-10 | ||
| 100.0.0.0/8 | ARIN | 2010-11 | 100.64.0.0/10 reserved for Carrier-grade NAT. | |
| 101.0.0.0/8 | APNIC | 2010-08 | ||
| 102.0.0.0/8 | AFRINIC | 2011-02 | ||
| 103.0.0.0/8 | APNIC | 2011-02 | ||
| 104.0.0.0/8 | ARIN | 2011-02 | ||
| 105.0.0.0/8 | AFRINIC | 2010-11 | ||
| 106.0.0.0/8 | APNIC | 2011-01 | ||
| 107.0.0.0/8 | ARIN | 2010-02 | ||
| 108.0.0.0/8 | ARIN | 2008-12 | ||
| 109.0.0.0/8 | RIPE NCC | 2009-01 | ||
| 110.0.0.0/8 | APNIC | 2008-11 | ||
| 111.0.0.0/8 | APNIC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 112.0.0.0/8 | APNIC | 2008-05 | ||
| 113.0.0.0/8 | APNIC | 2008-05 | ||
| 114.0.0.0/8 | APNIC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 115.0.0.0/8 | APNIC | 2007-10 | ||
| 116.0.0.0/8 | APNIC | 2007-01 | ||
| 117.0.0.0/8 | APNIC | 2007-01 | ||
| 118.0.0.0/8 | APNIC | 2007-01 | ||
| 119.0.0.0/8 | APNIC | 2007-01 | ||
| 120.0.0.0/8 | APNIC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 121.0.0.0/8 | APNIC | 2006-01 | ||
| 122.0.0.0/8 | APNIC | 2006-01 | ||
| 123.0.0.0/8 | APNIC | 2006-01 | ||
| 124.0.0.0/8 | APNIC | 2005-01 | ||
| 125.0.0.0/8 | APNIC | 2005-01 | ||
| 126.0.0.0/8 | APNIC | 2005-01 | SoftBank Group | |
| 128.0.0.0/8 | ARIN | 1993-05 | Various registries. 128.0.0.0 is the start address of formerly "Class B". | |
| 129.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 130.0.0.0/8 | Various registries | |||
| 131.0.0.0/8 | Various registries | |||
| 132.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 133.0.0.0/8 | APNIC | 1997-03 | JPNIC | |
| 134.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 135.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 136.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 137.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 138.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 139.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 140.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 141.0.0.0/8 | RIPE NCC | 1993-05 | Various registries. | |
| 142.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 143.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 144.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 145.0.0.0/8 | RIPE NCC | 1993-05 | Various registries. | |
| 146.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 147.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 148.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 149.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 150.0.0.0/8 | APNIC | 1993-05 | Various registries. | |
| 151.0.0.0/8 | RIPE NCC | 1993-05 | Various registries. | |
| 152.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 153.0.0.0/8 | APNIC | 1993-05 | Various registries. | |
| 154.0.0.0/8 | AFRINIC | 1993-05 | Various registries. | |
| 155.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 156.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 157.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 158.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 159.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 160.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 161.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 162.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 163.0.0.0/8 | APNIC | 1993-05 | Various registries. | |
| 164.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 165.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 166.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 167.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 168.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 169.0.0.0/8 | ARIN | 1993-05 | 1993-05-01 | Various registries. 169.254.0.0/16 reserved for link-local addressing. |
| 170.0.0.0/8 | ARIN | 1993-05 | Various registries. | |
| 171.0.0.0/8 | APNIC | 1993-05 | Various registries. | |
| 172.0.0.0/8 | ARIN | 1993-05 | 1993-05-01 | Various registries. 172.16.0.0/12 reserved for private networks. |
| 173.0.0.0/8 | ARIN | 2008-02 | ||
| 174.0.0.0/8 | ARIN | 2008-02 | ||
| 175.0.0.0/8 | APNIC | 2009-08 | ||
| 176.0.0.0/8 | RIPE NCC | 2010-05 | ||
| 177.0.0.0/8 | LACNIC | 2010-06 | ||
| 178.0.0.0/8 | RIPE NCC | 2009-01 | Various registries. | |
| 179.0.0.0/8 | LACNIC | 2011-02 | ||
| 180.0.0.0/8 | APNIC | 2009-04 | ||
| 181.0.0.0/8 | LACNIC | 2010-06 | ||
| 182.0.0.0/8 | APNIC | 2009-08 | ||
| 183.0.0.0/8 | APNIC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 184.0.0.0/8 | ARIN | 2008-12 | ||
| 185.0.0.0/8 | RIPE NCC | 2011-02 | Various registries. | |
| 186.0.0.0/8 | LACNIC | 2007-09 | ||
| 187.0.0.0/8 | LACNIC | 2007-09 | ||
| 188.0.0.0/8 | RIPE NCC | 1993-05 | Various registries. | |
| 189.0.0.0/8 | LACNIC | 1995-06 | ||
| 190.0.0.0/8 | LACNIC | 1995-06 | ||
| 191.0.0.0/8 | LACNIC | 1993-05 | Various registries. | |
| 192.0.0.0/8 | ARIN | 1993-05 | 1993-05-01 | Various registries. 192.0.2.0/24 reserved for TEST-NET-1. 192.88.99.0/24 reserved for 6to4 Relay Anycast. 192.168.0.0/16 reserved for private networks. 192.0.0.0/24 reserved for IANA IPv4 Special Purpose Address Registry. 192.0.0.0 is the start address of formerly "Class C". |
| 193.0.0.0/8 | RIPE NCC | 1993-05 | ||
| 194.0.0.0/8 | RIPE NCC | 1993-05 | ||
| 195.0.0.0/8 | RIPE NCC | 1993-05 | ||
| 196.0.0.0/8 | AFRINIC | 1993-05 | Various registries. | |
| 197.0.0.0/8 | AFRINIC | 2008-10 | ||
| 198.0.0.0/8 | ARIN | 1993-05 | Various registries. 198.18.0.0/15 reserved for Network Interconnect Device Benchmark Testing. 198.51.100.0/24 reserved for TEST-NET-2. | |
| 199.0.0.0/8 | ARIN | 1993-05 | ||
| 200.0.0.0/8 | LACNIC | 2002-11 | ||
| 201.0.0.0/8 | LACNIC | 2003-04 | ||
| 202.0.0.0/8 | APNIC | 2009-10 | Various registries. 202.123.0.0/19 transferred to AFRINIC | |
| 203.0.0.0/8 | APNIC | 1993-05 | 203.0.113.0/24 reserved for TEST-NET-3. | |
| 204.0.0.0/8 | ARIN | 1994-03 | ||
| 205.0.0.0/8 | ARIN | 1994-03 | ||
| 206.0.0.0/8 | ARIN | 1995-04 | ||
| 207.0.0.0/8 | ARIN | 1995-11 | ||
| 208.0.0.0/8 | ARIN | 1996-04 | ||
| 209.0.0.0/8 | ARIN | 1996-06 | ||
| 210.0.0.0/8 | APNIC | 1996-06 | ||
| 211.0.0.0/8 | APNIC | 1996-06 | ||
| 212.0.0.0/8 | RIPE NCC | 1997-10 | ||
| 213.0.0.0/8 | RIPE NCC | 1993-10 | ||
| 216.0.0.0/8 | ARIN | 1998-04 | ||
| 217.0.0.0/8 | RIPE NCC | 2000-06 | 2002-06-25 | |
| 218.0.0.0/8 | APNIC | 2010-01 | Formerly IANAReserved 1981-09. | |
| 219.0.0.0/8 | APNIC | 2001-09 | ||
| 220.0.0.0/8 | APNIC | 2001-12 | ||
| 221.0.0.0/8 | APNIC | 2002-07 | ||
| 222.0.0.0/8 | APNIC | 2003-02 | ||
| 223.0.0.0/8 | APNIC | 2010-04 |
Note that this list may not include current assignments of /8 blocks to all regional or national Internet registries.
Original list of IPv4 assigned address blocks
The original list of IPv4 address blocks was published in September 1981. In previous versions of the document, network numbers were 8-bit numbers rather than the 32-bit numbers used in IPv4. At that time, three networks were added that were not listed earlier: 42.rrr.rrr.rrr, 43.rrr.rrr.rrr, and 44.rrr.rrr.rrr.The relevant portion of RFC 790 is reproduced here with minor changes: