List of assigned /8 IPv4 address blocks

Some large /8 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 (ICANN), through the Internet Assigned Numbers Authority (IANA), or a regional Internet registry.

Each /8 block contains 256³ = 2²⁴ = 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 36.0.0.0/8, have returned their allocated blocks (in this case to APNIC) to assist in the delay of the exhaustion date.^{[citation needed]}

Block	Organization	IANA date	RIR date	Notes
0.0.0.0/8	IANA – Local Identification	1981-09		Originally IANA – Reserved 1981-09. 0.0.0.0/8 reserved for self-identification.^[1]
10.0.0.0/8	IANA – Private Use	1995-06		Reserved for Private Networks.^[2] Formerly ARPANET.^[3]
127.0.0.0/8	IANA – Loopback	1981-09		127.0.0.0/8 is reserved for loopback.^[1]
224.0.0.0/8–239.0.0.0/8	Multicast	1981-09	1991-05-22	Multicast (formerly "Class D"^[4]) registered in multicast addresses
240.0.0.0/8–255.0.0.0/8	Future Use	1981-09		Reserved for future use (formerly "Class E"^[5]). 255.255.255.255 is reserved for "limited broadcast" destination address.^[6]^[7]

Block	Organization	IANA date	RIR date	Notes
12.0.0.0/8	AT&T Services	1995-06	1983-08-23	Originally AT&T Bell Laboratories, but retained by AT&T when Bell Labs was spun off to Lucent Technologies in 1996. Assignment administered by ARIN (Legacy space).
17.0.0.0/8	Apple Inc.	1992-07	1990-04-16	Assignment administered by ARIN (Legacy space)
19.0.0.0/8	Ford Motor Company	1995-05	1988-06-15	Assignment administered by ARIN (Legacy space)
38.0.0.0/8	Cogent Communications	1994-09	1991-04-16	Formerly PSINet. As of 2025, portions of this range are leased to local ISPs. Assignment administered by ARIN (Legacy space)
53.0.0.0/8	Mercedes-Benz Group AG	1993-10	1970-01-01	Assignment administered by RIPE (Legacy space)
73.0.0.0/8	Comcast Corporation^[8]	N/A	2005-04-19	Assignment administered by ARIN

Block	Organization	IANA date	RIR date	Notes
6.0.0.0/8	Army Information Systems Center	1994-02	1994-02-01	Headquarters, USAISC
7.0.0.0/8	DoD Network Information Center	1995-04	1997-11-24	Formerly IANA – Reserved 1995-04. Entirely assigned to DoD Network Information Center (DNIC) 1997-11-24. Updated to Administered by ARIN not before 2007.
11.0.0.0/8	DoD Intel Information Systems	1993-05	1984-01-19
21.0.0.0/8	DDN-RVN	1991-07	1991-07-01	DoD Network Information Center (DNIC)
22.0.0.0/8	Defense Information Systems Agency	1993-05	1989-06-26	DoD Network Information Center (DNIC)
26.0.0.0/8	Defense Information Systems Agency	1995-05	1995-05-01	DoD Network Information Center (DNIC)
28.0.0.0/8	DSI-North	1992-07		DoD Network Information Center (DNIC)
29.0.0.0/8	Defense Information Systems Agency	1991-07	1991-07-01	DoD Network Information Center (DNIC)
30.0.0.0/8	Defense Information Systems Agency	1991-07	1991-07-01	DoD Network Information Center (DNIC)
33.0.0.0/8	DLA Systems Automation Center	1991-01	1991-01-01	DoD Network Information Center (DNIC)
55.0.0.0/8	DoD Network Information Center	1995-04	1996-10-26	Headquarters, USAISC. Formerly Boeing Computer Services 1995-04. Updated to DoD Network Information Center in 2007-02.
214.0.0.0/8	US-DOD	1998-03	1998-03-27	DoD Network Information Center (DNIC)
215.0.0.0/8	US-DOD	1998-03	1998-06-05	DoD Network Information Center (DNIC)

List of assigned /8 IPv4 address blocks

List of reserved /8 blocks

List of /8 blocks assigned to commercial organizations

List of /8 blocks assigned to the United States Department of Defense

List of /8 blocks assigned to the regional Internet registries

Original list of IPv4 assigned address blocks

See also

Notes

References

Wikiwand - on

Block	Organization	IANA date	RIR date	Notes
1.0.0.0/8	APNIC	2010-01		Formerly IANA – reserved 1981-09.
2.0.0.0/8	RIPE NCC	2009-10		Formerly IANA – reserved 1981-09.
3.0.0.0/8	ARIN	1994-05		Amazon.com.^[9] Formerly General Electric Company.
4.0.0.0/8	ARIN	1992-12		Various registries (maintained by ARIN). 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 IANA – reserved 1995-07.
8.0.0.0/8	ARIN	1992-12	1992-12-01	Various registries (maintained by ARIN). 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 (maintained by ARIN). Formerly Xerox.
14.0.0.0/8	APNIC	2010-04		Starting 1991-06-01, was used to map Public Data Network (X.121) 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.^[10]
15.0.0.0/8	ARIN	1991-09		Various registries (maintained by ARIN). 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 (maintained by ARIN). Formerly Digital Equipment Corporation, then Compaq, then Hewlett-Packard.
18.0.0.0/8	ARIN	1994-01		Various registries (maintained by ARIN). Formerly MIT.
20.0.0.0/8	ARIN	1994-10		Various registries (maintained by ARIN). Formerly DXC Technology. Computer Sciences Corporation, who owned this block, merged with HP Enterprise Services to create DXC Technology on 3 April 2017.^[11]^[12]
23.0.0.0/8	ARIN	2010-11		Formerly IANA – reserved 1995-07.
24.0.0.0/8	ARIN	2001-05	2001-05-01	Formerly IANA – Cable Block 1995-07, then ARIN – Cable Block 2001-05.^[13] 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 IANA – reserved 1995-04.
31.0.0.0/8	RIPE NCC	2010-05	2010-05-18	Formerly IANA – reserved 1991-04.
32.0.0.0/8	ARIN	1994-06		Various registries (maintained by ARIN). Formerly AT&T Global Network Services. Originally Norsk Informasjonsteknologi (at that time maintained by RIPE NCC). IBM acquired Norsk Informasjonsteknologi (Norway) in 1995.
34.0.0.0/8	ARIN	1993-03		Various registries (maintained by ARIN). Formerly Halliburton Company.
35.0.0.0/8	ARIN	1994-04	2012-08	Various registries (Maintained by ARIN). Formerly Merit Network 1986.
36.0.0.0/8	APNIC	2010-10		Formerly Stanford University 1993-04, then IANA – Reserved 2000-07.
37.0.0.0/8	RIPE NCC	2010-11		Formerly IANA – Reserved 1995-04.
39.0.0.0/8	APNIC	2011-01		Formerly IANA – Reserved 1995-04.
40.0.0.0/8	ARIN	1994-06		Various registries (Maintained by ARIN).
41.0.0.0/8	AFRINIC	2005-04		Formerly IANA – Reserved 1995-05.
42.0.0.0/8	APNIC	2010-10		Formerly IANA – Reserved 1995-07.
43.0.0.0/8	APNIC	1991-01	1989-02-21	Various registries (Maintained by APNIC). Originally Japan Inet 1991-01 (IANA date) or 1989-02-21 (RIR date). Administered by APNIC not before 2007.
44.0.0.0/8	ARIN	1992-07	2019-07-18	Various registries (Maintained by ARIN). Originally Amateur Radio Digital Communications. 44.192.0.0/10 was sold to Amazon on 2019-07-18.^[14]
45.0.0.0/8	ARIN	1995-01	1991-09-09	Various registries (Maintained by ARIN). Formerly Interop Show Network 1995-01 or 1991-09-09 (RIR date). Returned to ARIN in 2010-10 except a /15 block. In 2011 it became available for distribution (or possibly be returned to the IANA, depending on the global policy in effect at that time).^[15]
46.0.0.0/8	RIPE NCC	2009-09		Formerly Bolt Beranek and Newman Inc. 1992-12. Returned to IANA in 2007-04.^[16] Updated to IANA – Reserved in 2007-04.
47.0.0.0/8	ARIN	1991-01		Various registries (Maintained by ARIN). 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 (Legacy space). Formerly Prudential Financial, who still use a portion of the space.
49.0.0.0/8	APNIC	2010-08		Formerly Joint Technical Command (Returned to IANA Mar 98) 1994-05. Updated to IANA – Reserved in 2007-05.
50.0.0.0/8	ARIN	2010-02		Formerly Joint Technical Command (Returned to IANA Mar 98) 1994-05. Updated to IANA – Reserved in 2007-05.
51.0.0.0/8	RIPE NCC	1994-08		Various registries (Maintained by RIPE NCC). 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 (Maintained by ARIN).
56.0.0.0/8	ARIN	1992-11		Formerly United States Postal Service.
57.0.0.0/8	RIPE NCC	1995-05		Formerly SITA.