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.
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 . |
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. 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) |
The regional Internet registries (RIRs) 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 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. | |
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 IANA - Reserved 1981-09. | |
61.0.0.0/8 | APNIC | 2010-01 | Formerly IANA - Reserved 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 IANA - Reserved 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 | Fastweb.it. [17] | |
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 (detailed in RFC 6598). | |
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 IANA - Reserved 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 IANA - Reserved 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 IANA - Reserved 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 Corp. | |
128.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). 128.0.0.0 is the start address of formerly "Class B". | |
129.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
130.0.0.0/8 | Various registries | |||
131.0.0.0/8 | Various registries | |||
132.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
133.0.0.0/8 | APNIC | 1997-03 | JPNIC [18] | |
134.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
135.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
136.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
137.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
138.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
139.0.0.0/8 | MIX | Various registries | ||
140.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
141.0.0.0/8 | RIPE NCC | 1993-05 | Various registries (Maintained by RIPE NCC). | |
142.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
143.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
144.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
145.0.0.0/8 | RIPE NCC | 1993-05 | Various registries (Maintained by RIPE NCC). | |
146.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
147.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
148.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
149.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
150.0.0.0/8 | APNIC | 1993-05 | Various registries (Maintained by APNIC). | |
151.0.0.0/8 | RIPE NCC | 1993-05 | Various registries (Maintained by RIPE NCC). | |
152.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
153.0.0.0/8 | APNIC | 1993-05 | Various registries (Maintained by APNIC). | |
154.0.0.0/8 | AFRINIC | 1993-05 | Various registries (Maintained by AFRINIC). | |
155.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
156.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
157.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
158.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
159.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
160.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
161.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
162.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
163.0.0.0/8 | APNIC | 1993-05 | Various registries (Maintained by APNIC). | |
164.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
165.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
166.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
167.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
168.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
169.0.0.0/8 | ARIN | 1993-05 | 1993-05-01 | Various registries (Maintained by ARIN). 169.254.0.0/16 (169.254.0.0–169.254.255.255) reserved for link-local addressing (RFC 6890). |
170.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). | |
171.0.0.0/8 | APNIC | 1993-05 | Various registries (Maintained by APNIC). | |
172.0.0.0/8 | ARIN | 1993-05 | 1993-05-01 | Various registries (Maintained by ARIN). 172.16.0.0/12 (172.16.0.0–172.31.255.255) reserved for private networks (RFC 1918). |
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 (Maintained by RIPE NCC). | |
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 IANA - Reserved 1981-09. | |
184.0.0.0/8 | ARIN | 2008-12 | ||
185.0.0.0/8 | RIPE NCC | 2011-02 | Various registries (Maintained by RIPE NCC). | |
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 (Maintained by RIPE NCC). | |
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 (Maintained by LACNIC). | |
192.0.0.0/8 | ARIN | 1993-05 | 1993-05-01 | Various registries (Maintained by ARIN). 192.0.2.0/24 reserved for TEST-NET-1 (RFC 5737). 192.88.99.0/24 reserved for 6to4 Relay Anycast (RFC 3068). 192.168.0.0/16 (192.168.0.0–192.168.255.255) reserved for private networks (RFC 1918). 192.0.0.0/24 reserved for IANA IPv4 Special Purpose Address Registry (RFC 5736). 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 (Maintained by AFRINIC). | |
197.0.0.0/8 | AFRINIC | 2008-10 | ||
198.0.0.0/8 | ARIN | 1993-05 | Various registries (Maintained by ARIN). 198.18.0.0/15 reserved for Network Interconnect Device Benchmark Testing (RFC 6890). 198.51.100.0/24 reserved for TEST-NET-2 (RFC 5737). | |
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 (Maintained by APNIC). 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 (RFC 5737). | |
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 IANA - Reserved 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.
The original list of IPv4 address blocks was published in September 1981. [3] In previous versions of the document, [19] [20] 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:
An Internet Protocol address is a numerical label such as 192.0.2.1 that is assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface identification, and location addressing.
Internet Protocol version 4 (IPv4) is the first version of the Internet Protocol (IP) as a standalone specification. It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version deployed for production on SATNET in 1982 and on the ARPANET in January 1983. It is still used to route most Internet traffic today, even with the ongoing deployment of Internet Protocol version 6 (IPv6), its successor.
Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion, and was intended to replace IPv4. In December 1998, IPv6 became a Draft Standard for the IETF, which subsequently ratified it as an Internet Standard on 14 July 2017.
In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages to other hosts on an Internet Protocol (IP) network. Within an IP network, UDP does not require prior communication to set up communication channels or data paths.
A multicast address is a logical identifier for a group of hosts in a computer network that are available to process datagrams or frames intended to be multicast for a designated network service. Multicast addressing can be used in the link layer, such as Ethernet multicast, and at the internet layer for Internet Protocol Version 4 (IPv4) or Version 6 (IPv6) multicast.
In computing, Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs).
The Address Resolution Protocol (ARP) is a communication protocol used for discovering the link layer address, such as a MAC address, associated with a given internet layer address, typically an IPv4 address. This mapping is a critical function in the Internet protocol suite. ARP was defined in 1982 by RFC 826, which is Internet Standard STD 37.
The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System (DNS), media types, and other Internet Protocol–related symbols and Internet numbers.
A subnetwork, or subnet, is a logical subdivision of an IP network. The practice of dividing a network into two or more networks is called subnetting.
A classful network is an obsolete network addressing architecture used in the Internet from 1981 until the introduction of Classless Inter-Domain Routing (CIDR) in 1993. The method divides the IP address space for Internet Protocol version 4 (IPv4) into five address classes based on the leading four address bits. Classes A, B, and C provide unicast addresses for networks of three different network sizes. Class D is for multicast networking and the class E address range is reserved for future or experimental purposes.
Bogon filtering is the practice of blocking packets known as bogons, which are ones sent to a computer network claiming to originate from invalid or bogus IP addresses, known as bogon addresses.
A Martian packet is an IP packet seen on the public Internet that contains a source or destination address that is reserved for special use by the Internet Assigned Numbers Authority (IANA) as defined in RFC 1812, Appendix B Glossary. On the public Internet, such a packet either has a spoofed source address, and it cannot actually originate as claimed, or the packet cannot be delivered. The requirement to filter these packets is found in RFC 1812, Section 5.3.7.
In computer networking, localhost is a hostname that refers to the current computer used to access it. The name localhost is reserved for loopback purposes. It is used to access the network services that are running on the host via the loopback network interface. Using the loopback interface bypasses any local network interface hardware.
In Internet networking, a private network is a computer network that uses a private address space of IP addresses. These addresses are commonly used for local area networks (LANs) in residential, office, and enterprise environments. Both the IPv4 and the IPv6 specifications define private IP address ranges.
In the Internet addressing architecture, the Internet Engineering Task Force (IETF) and the Internet Assigned Numbers Authority (IANA) have reserved various Internet Protocol (IP) addresses for special purposes.
A unique local address (ULA) is an Internet Protocol version 6 (IPv6) address in the address range fc00::/7. These addresses are non-globally reachable. For this reason, ULAs are somewhat analogous to IPv4 private network addressing, but with significant differences. Unique local addresses may be used freely, without centralized registration, inside a single site or organization or spanning a limited number of sites or organizations.
The Internet Protocol Version 4 address 0.0.0.0 can have multiple uses.
An Internet Protocol version 6 address is a numeric label that is used to identify and locate a network interface of a computer or a network node participating in a computer network using IPv6. IP addresses are included in the packet header to indicate the source and the destination of each packet. The IP address of the destination is used to make decisions about routing IP packets to other networks.
An IPv6 packet is the smallest message entity exchanged using Internet Protocol version 6 (IPv6). Packets consist of control information for addressing and routing and a payload of user data. The control information in IPv6 packets is subdivided into a mandatory fixed header and optional extension headers. The payload of an IPv6 packet is typically a datagram or segment of the higher-level transport layer protocol, but may be data for an internet layer or link layer instead.
In order to ensure proper working of carrier-grade NAT (CGN), and, by doing so, alleviating the demand for the last remaining IPv4 addresses, a /10 size IPv4 address block was assigned by Internet Assigned Numbers Authority (IANA) to be used as shared address space. This block of addresses is specifically meant to be used by Internet service providers that implement carrier-grade NAT, to connect their customer-premises equipment (CPE) to their core routers.