IP Network Numbers - Class A

Class A networks (0.x.x.x to 127.x.x.x) have an 8-bit network prefix with a 32-bit host number, and are also referred to as /8 networks.

The first bit is set to 0 to identify the network as a Class A type; this results in 128 (2⁷) possible Class A networks, but those with prefix 0 and 127 are used for special functions and the upper half (with prefixes above 64) are reserved for future use.

This information was updated November 1999.

0 Internet Assigned Numbers Authority (IANA) (NET-RESERVED-1)

1 Internet Assigned Numbers Authority (IANA-ARIN) (NET-RESERVED-9)

2 Internet Assigned Numbers Authority (IANA) (NET-RESERVED-2)

3 General Electric Company, NJ (NET-GE-INTERNET)

4 BBN Planet, MA (NET-SATNET)

5 Internet Assigned Numbers Authority (IANA) (NET-RESERVED-5)

6 Army Information Systems Center - USAISC, Yuma Proving Ground, AZ (NET-YPG-NET)

7 Defense Information Systems Agency, VA (NET-DISANET2)

8 Bolt Beranek and Newman Inc., MA (NET-BBN-NET-TEMP)

9 IBM Corporation, NY (NET-IBM)

10 Internet Assigned Numbers Authority (IANA) (RESERVED-6)
This is reserved for private internet use, without connection to the global network

11 DoD Intel Information Systems, Defense Intelligence Agency, Washington DC (NET-DODIIS)

12 AT&T (NET-ATT)

13 Xerox Palo Alto Research Center, CA (NET-XEROX-NET)

14 Public Data Network, US (NET-PDN)

15 Hewlett-Packard Company, CA (NET-HP-INTERNET)

16 Digital Equipment Corporation (NET-DEC-INTERNET)

17 Apple Computer Inc., CA (NET-APPLE-WWNET)

18 Massachusetts Institute of Technology, MA (NET-MIT-TEMP)

19 Ford Motor Company, MI (NET-FINET)

20 Computer Sciences Corporation, VA (NET-CSC)

21 US Defense Information Systems Agency (DDN-RVN), VA (NET-DDN-RVN)

22 Defense Information Systems Agency, Washington DC (NET-DISNET)

23 IANA (reserved) (NET-DDN-TC-NET) (RESERVED-23)

24 US Cable Networks

25 Royal Signals and Radar Establishment, UK (NET-RSRE-EXP)

26 Defense Information Systems Agency, VA (NET-MILNET)

27 Internet Assigned Numbers Authority (IANA) (RESERVED-10)

28 ARPA DSI JPO, VA (NET-DSI-NORTH)

29 Defense Information Systems Agency, Washington DC (NET-MILX25-TEMP)

30 Defense Information Systems Agency, Washington DC (NET-ARPAX25-TEMP)

31 IANA (RESERVED-12)

32 IBM Global Services, NH (NETBLK-IBMGLOBALSERV)

33 DLA Systems Automation Center, OH (NET-DCMC)

34 Halliburton Company, TX (NET-HALLIBURTON)

35 MERIT Network Inc., MI (NET-MERIT)

36 Stanford University, CA (NET-SU-NET-TEMP)

37 Internet Assigned Numbers Authority (IANA) (RESERVED-37A)

38 Performance Systems International, VA (NET-PSINETA)

39 Internet Assigned Numbers Authority (IANA) (RESERVED-39A)

40 Eli Lilly and Company, IN (NET-LILLY-NET)

41 Internet Assigned Numbers Authority (RESERVED-41A)

42 Internet Assigned Numbers Authority (IANA) (RESERVED) (NET-RESERVED-42)

43 Japan Inet, Japan (NET-JAPAN-A)

44 Amateur Radio Digital Communications (NET-AMPRNET)

45 Interop Show Network, CA (NET-SHOWNETA)

46 Bolt Beranek and Newman Inc., MA (NET-BBNNET)

47 Bell-Northern Research, Canada (NET-BNR)

48 Prudential Securities Inc., NY (NET-PRUBACHE)

49 Joint Tactical Command, Control, and Communications Agency, AZ (NET-JITCNET1)

50 Joint Tactical Command, Control, and Communications Agency, AZ (NET-JITCNET2)

51 Department of Social Security of UK, England (NET-ITSANET)

52 E.I. duPont de Nemours and Co., Inc., DE (NET-DUPONT1)

53 cap debis ccs (Mercedes Benz), Germany (NET-DB-NET2)

54 Merck and Co., Inc., NJ (NET-MERCK2)

55 Army National Guard Bureau, VA (NET-RCAS2)

56 U.S. Postal Service, NC (NET-USPS1)

57 SITA - Societe Internationale de Telecommunications Aeronautiques, France (NET-SITA2)

58 Internet Assigned Numbers Authority (IANA) (RESERVED) (NET-RESERVED-58)

59 Internet Assigned Numbers Authority (IANA) (RESERVED) (NET-RESERVED-59)

60 Internet Assigned Numbers Authority (IANA) (RESERVED) (NET-RESERVED-60)

61 Asia Pacific Network Information Center (NETBLK-APNIC2)

62 European Regional Internet Registry/RIPE NCC (NETBLK-RIPE-C3)

63 InterNIC Registration (NETBLK-INTERNIC-2)

64 - 95 Internet Assigned Numbers Authority (IANA) (RESERVED-7)

96 - 126 Internet Assigned Numbers Authority (IANA) (RESERVED-8)

127 Internet Assigned Numbers Authority (IANA) (LOOPBACK)

IP Network Numbers - Class B

Class B networks (128.0.x.x to 191.255.x.x) have a 16-bit network prefix with a 16-bit host number, and are also referred to as /16 networks.

The first two bits of the prefix are set to 10, hence there are 2¹⁴ (16384) possible Class B networks; currently around 12000 are defined (65%).

This information was updated September 2000.

173 - 191 Not yet used.

IP Network Numbers - Class C

Class C networks (192.0.0.x to 223.255.255.x) require 24 bits to identify the network, leaving 8 to identity the host, and are also referred to as /24 networks.

The first three bits of the network prefix are set to 110, hence there are 2²¹ (2097152) possible Class C networks; currently around 800000 are defined (40%).

Class C Networks - Block 212

These are allocated to European organisations; the particular country is indicated by the two-letter country code given on this page and on the individual sections.

[212.0 EU/RU/ES/SD/PT/MD/NL]; [212.1 IT/NL/DE/UA/GB/RU]; [212.2 GB/DE/IT/TR/SA]; [212.3 SE/HU/UA/DE/IL/NL/BE]; [212.4 IT/NO/CH/ES/RU/DE/CH]; [212.5 DE/RU/AZ/BG/SK/RU]; [212.6 RU/DE]; [212.7 EE/ES/IT/DE/BG/RU]; [212.8 DE/UA/ES/BE/DE/RU]; [212.9 GB/DK/ES/GB/DE/UA]; [212.10 DK]; [212.11 FR/IT/CZ/RU/SA/RU/DE]; [212.12 DE/RU/DE/TR/SA/IT/EG]; [212.13 IT/MK//RU/KZ/GB/SI]; [212.14 PL/DE/IT/RU/PS]; [212.15 TR/GB/RU/UA/IT/DE/ES]; [212.16 RU/AT/FR/FI/PT/SE/RU/DE]; [212.17 RU/IE/AT/IT/DE]; [212.18 DE/CH/NO/PT/GB]; [212.19 RU/DE/GB/IT/KZ/FR/NL]; [212.20 RU/CZ/DE/NO/GB]

[212.21 GB/DE/GB/BG/IT]; [212.22 GB/ES/RU/GB/IT]; [212.23 GB/RU/DE/FR/CH/GB]; [212.24 IT/RU/GB/AT/CZ/LU/SA]; [212.25 CH/DE/IL/ES/IT/NL/GB]; [212.26 SA/UA/SK/NL/RU]; [212.27 RU/FR/AT/DE/CH/CZ/EE]; [212.28 GB/DE/RU/CH/SE/DE]; [212.29 DE/TR/IT/NL/IL]; [212.30 GB/GR/SI/FR/RU/IS]; [212.31 TR/ES/AT/CY/FR/SE/ES/IT]; [212.32 GB/SE/RU/NL]; [212.33 TR/AT/PL/NO/JO/RU]; [212.34 JO/RU/DE/ES/IT]; [212.35 BE/CH/JO/RO/UA/IT/GB]; [212.36 BG/GB/DE/LB]; [212.37 SE/DE/GR/SE/NL/GB/FR/NO]; [212.38 DE/IT/GB/RU/AZ/JO/CH/FI]; [212.39 IT/SE/BG/BA/FR/GB]; [212.40 CH/UA/HU/FR/RU/ES]

[212.41 RU/DE/NL/IT/AT]; [212.42 GB/RU/UA/KG/CH/AM/DE]; [212.43 KW/DE/CH/GB/FR]; [212.44 GB/RU/ES/CU/RU/DE/FR]; [212.45 RU/NL/TR/IT/NO/CH/PL]; [212.46 RU/SA/GB/DE/RU]; [212.47 CZ/GB/LT/AZ/CH/EE/FR]; [212.48 IT/NL/PT/RU/TR]; [212.49 EE/KE/RU/ES/GB]; [212.50 BG/TR/IT/EG/FI/GB]; [212.51 DE/ES/HU/IT/FR/PL/AT]; [212.52 NL/IT/BF/HU/AT/DE]; [212.53 BE/RU/GB/CH/DE]; [212.54 FI/DK/PT/GR/IT]; [212.55 ES/FO/GB/DE/PT/CH/SK]; [212.56 BG/GB/MT/MD/LU]; [212.57 TR/GB/DE/RU/GB]; [212.58 TR/GB/DE/GB/NL/RU]; [212.59 LT/DE/GB/CH/ES/IT]; [212.60 DE/CH/GM/DE/AT]

[212.61 NL] [212.62 various]; [212.63 various]; [212.64 NL/SA/ES/TR]; [212.65 DE/BE/LU/DE/TR/PL/CZ]; [212.66 DE/UA/LU/IT/ES/FI]; [212.67 RU/FR/CZ/GB/NL]; [212.68 FI/DE/IL/BE]; [212.69 BA/GB/PL/RU/IT/AT]; [212.70 DK/SA/GB/AT/LV/GR]; [212.71 BE/NO/CH/CZ/DE/IT]; [212.72 OM/NL/DE/CZ/GE/BG]; [212.73 SE/AM/RU/DE/FR]; [212.74 GB/CH/DE]; [212.75 IT/DE/SE/PL/HU/ES/GR]; [212.76 KZ/PL/SA/HU/DE]; [212.77 VA/LI/IT/IL/DE/DE/QA]; [212.78 IT/FR/GB/DE/ES/NL/SE]; [212.79 DE/BE/ES]; [212.80 BE/DE/CZ/CH/ES/GB/IT]

[212.81 SK/FR/ES]; [212.82 GB/DE/FR/UA]; [212.83 RU/NL/FI/FR]; [212.84 NL/IT/DE]; [212.85 GB/SE/FR/IT]; [212.86 FI/DE/UA/DE]; [212.87 PL/DE/GB/ES]; [212.88 AT/GB/DK/UG/DE/AT]; [212.89 ES/GB/DE/GR]; [212.90 IT/GB/FI/DE/UA/CH]; [212.91 GB/IT/HR/SE/BG/RU]; [212.92 HU/NL/RU/GB]; [212.93 DE/GB/RO/SA]; [212.94 SE/FI/RU/IT/FR]; [212.95 AT/FR/GB/ES]; [212.96 DE/CZ/RU]; [212.97 HU/IT/GB/DE/ES/DK]; [212.98 TR/CH/DE/LB/BY/TR]; [212.99 DE]; [212.100 GB/NG/GB/RU/BE/SA]

[212.101 CH/DE/ES/TR]; [212.102 SA/IT/GB/YU/DE]; [212.103 FR/DE/CH/SI/EG/IT]; [212.104 IT/GB/IT/NL]; [212.105 SE/BE/GB/DE]; [212.106 PL/GB/SA/ES]; [212.107 GR/FR/GB]; [212.108 NL/AT/GB/RU/TR/DE/HU]; [212.109 SE/UA/CH/TR/PL/RU]; [212.110 IT/MK/DE/UA]; [212.111 CZ/GB/RU/UA]; [212.112 SE/IT/KG/DK/SE/DE]; [212.113 GB/UA/BE/RU/PT]; [212.114 RU/DE]; [212.115 TR/IT/NL]; [212.116 DE/FI/SE/BG/IL/SA]; [212.117 GB/NL/DE/CH/IL]; [212.118 JO/DE/SI/SA]; [212.119 GB/SA/AT/RU];
[212.120 MK/DE/NL/IE/RU/GR]

[212.121 GB/IT/DE]; [212.122 RU/BE/LT/ES/DE/CZ/PL]; [212.123 BE/DE/IT/NL]; [212.124 FR/DE/BG/NL/AT/YU]; [212.125 TR/GB/DE/NL/NO]; [212.126 PL/GB/CH/DE]; [212.127 GB/DE/PL/TR/NL]; [212.128 ES]; [212.129 FR]; [212.130 DK]; [212.131 IT]; [212.132 GB]; [212.133 ES/FR/GB/IT/TR]; [212.134 GB]; [212.135 GB]; [212.136 IT]; [212.137 GB]; [212.138 SA]; [212.139 GB]; [212.140 GB]

[212.141 IT]; [212.142 NL]; [212.143 IL]; [212.144 DE]; [212.145 ES]; [212.146 FI]; [212.147 CH]; [212.148 GB]; [212.149 DE]; [212.150 IL]; [212.151 SE]; [212.152 CH/AT]; [212.153 NL]; [212.154 TR/KZ]; [212.155 FR]; [212.156 TR]; [212.157 FR]; [212.158 GB/RU]; [212.159 GB]; [212.160 PL]

[212.161 GB/CH]; [212.162 DE/SA]; [212.163 ES]; [212.164 RU]; [212.165 AT]; [212.166 BE]; [212.169 GB]; [212.170 ES]; [212.171 IT]; [212.172 DE/IT]; [212.173 GB]; [212.174 TR]; [212.175 TR]; [212.176 RU]; [212.177 IT]; [212.178 NL]; [212.179 IL]; [212.180 FR]

[212.181 SE]; [212.182 PL]; [212.183 AT]; [212.184 DE]; [212.185 DE]; [212.186 AT/NO]; [212.187 NL]; [212.188 RU]; [212.189 NL]; [212.190 BE]; [212.191 PL]; [212.192 RU]; [212.193 RU]; [212.194 FR]; [212.196 GB]; [212.197 SK]; [212.198 FR]; [212.199 IL]; [212.200 YU]

[212.201 DE]; [212.202 DE]; [212.203 NL]; [212.204 DE/NL]; [212.205 GR]; [212.206 NL]; [212.207 GB]; [212.208 FR]; [212.209 SE]; [212.210 IT]; [212.211 GB]; [212.212 GB]; [212.213 FI]; [212.214 SE]; [212.215 CH]; [212.216 IT]; [212.217 MA]; [212.218 DE]; [212.219 GB]; [212.220 RU]

[212.221 BE]; [212.222 DE]; [212.223 DE]; [212.224 DE]; [212.225 GB]; [212.226 FI]; [212.227 DE]; [212.228 GB]; [212.231 ES]; [212.232 FR]; [212.233 BE]; [212.234 FR]; [212.235 IL]; [212.236 AT]; [212.237 DK]; [212.238 NL]; [212.239 IT]; [212.240 GB]

[212.241 FR]; [212.242 DK]; [212.243 CH]; [212.244 PL]; [212.245 IT]; [212.246 FI]; [212.247 SE]; [212.248 RU]; [212.249 CH]; [212.250 GB]; [212.251 GR]; [212.252 TR]; [212.254 CH]; [212.255 DE];

Class C Networks - Block 213

These are allocated to European/Middle Eastern/African organisations; the particular country is indicated by the two-letter country code given on this page and on the individual sections.

[213.0 ES]; [213.1 GB]; [213.2 GB]; [213.3 CH/LI]; [213.4 ES]; [213.5 GB]; [213.6 DE/GB]; [213.7 DE]; [213.8 IL]; [213.9 DE]; [213.10 NL]; [213.11 FR]; [213.12 GB]; [213.13 PT]; [213.14 TR]; [213.15 SE]; [213.16 FR/MQ]; [213.17 NL]; [213.18 GB]; [213.19 FR]; [213.20 DE]

[213.21 DE]; [213.22 PT]; [213.23 DE]; [213.24 RU]; [213.25 PL]; [213.26 IT]; [213.28 FI]; [213.29 IR]; [213.30 PT]; [213.32 DK]; [213.33 AT]; [213.34 NL]; [213.35 NL]; [213.36 FR]; [213.37 ES]; [213.38 GB]; [213.39 FR/CH]

[213.41 FR]; [213.42 AE]; [213.43 TR]; [213.44 FR]; [213.45 IT]; [213.46 NL]; [213.47 AT]; [213.48 GB]; [213.49 BE]; [213.50 SE]; [213.51 NL]; [213.52 ES]; [213.53 NL]; [213.54 DE]; [213.55 GB/ET/CH]; [213.56 FR]; [213.57 IL]; [213.58 PT]; [213.59 RU]; [213.60 ES]

[213.61 DE] [213.62 various]; [213.63 PT]; [213.68 DE]; [213.69 DE]; [213.72 GB]; [213.73 GB]; [213.74 TR]; [213.75 NL]; [213.76 PL]; [213.77 PL]; [213.78 FR]; [213.79 DE]; [213.80 SE]

[213.81 GB]; [213.82 IT]; [213.83 DE]; [213.84 NL]; [213.85 RU]; [213.86 GB]; [213.87 RU]; [213.88 SE]; [213.89 SE]; [213.90 AT]; [213.91 FR]; [213.92 IT]; [213.93 NL]; [213.94 ES]; [213.95 DE]; [213.96 PL]; [213.98 ES]; [213.99 ES]; [213.100 SE]

[213.104 GB]; [213.105 GB/IE]; [213.106 GB]; [213.107 GB]; [213.112 SE]; [213.115 SE]; [213.116 EU]; [213.120 GB]

[213.121 GB]; [213.123 GB]; [213.124 NL]; [213.125 NL]; [213.126 NL]; [213.127 NL]; =[213.128 DE/FR/RU]; [213.129 DK/PT/NL]; [213.130 UA/BG/GB/FI]; [213.131 RU/EG/SE/DE]; [213.132 DK/RU/BE/NL]; [213.133 DK/GB]; [213.134 HU/IT/PL/RU]; [213.135 DE/RU/IT]; [213.136 NL/DE/IT/SA]; [213.137 GB/IL/MC/DE]; [213.138 TR/RU/FI/RU]; [213.139 ES/DE/TR]; [213.140 IT/GR/IT]

[213.141 PT/SE/RU]; [213.142 SE/NO/GR/RU]; [213.143 GB]; [213.144 DE/IT/CH/IT]; [213.145 IT/DE/KG/PT]; [213.146 CH/SE/GB/PT]; [213.147 DE/KE/RU/AT]; [213.148 RU/TR/DE/GB]; [213.149 PL/DE/ES/NO]; [213.150 AT/RU/SE/ES]; [213.151 IL/CZ/NO/SK]; [213.152 GR/EG/RU/IT]; [213.153 IE/DE/TR]; [213.154 GB/SN/RO/UA]; [213.155 DE/GB/IT]; [213.156 NL/UA/RU]; [213.157 DE/FI/AT/GE]; [213.158 RU/IT/CH/PL]; [213.159 NL/RU/IE/IT]; [213.160 DE/UA/DE]

[213.161 SI/GB/TR/FR]; [213.162 CH/AT/SE/ES]; [213.163 HU/GB/SE/GB]; [213.164 AT/DE/SE/BE]; [213.165 GB/DE/GB/RU]; [213.166 GB/SA/FR]; [213.167 FR/GB/IS/IT]; [213.168 EE/DE]; [213.169 FI/UA/CY/NL]; [213.170 GB/RU/GB/GR]; [213.171 DE/NL/GB]; [213.172 RU/AZ/GH/NO]; [213.173 DE/FI/PL]; [213.174 BG/DK/CH/GB]; [213.175 IT/LV/AT/GB]; [213.176 IR/IS/DE]; [213.177 GB/CH/BE/GB]; [213.178 DE/GB/IT]; [213.179 SE/DE]; [213.180 EE/SE/PL/RU]

[213.181 RU/NG/NL/PL]; [213.182 DE/GB/DE/LV]; [213.183 DE/GR/IT]; [213.184 PL/RU/NO]; [213.185 IT/DE/GB]; [213.186 GB/PL/TR/UA]; [213.187 DE/SA/NL/SE]; [213.188 NO/FR/NO/IT]; [213.189 NL/KW/CH/RU]; [213.190 LB/FR/IE/PT]; [213.191 DE/HR/FI/HR]; [213.192 IT/FI]; [213.193 FR]; [213.194 NL/ES]; [213.195 FR]; [213.196 NL/CH]; [213.197 NL]; [213.198 DE/IT]; [213.199 IT]; [213.200 CH/SE]

[213.201 ES]; [213.202 TR/IE]; [213.203 NO]; [213.204 IT/SE]; [213.205 IT]; [213.206 GB]; [213.207 NL]; [213.208 AT]; [213.209 IT]; [213.210 BG/CZ]; [213.211 ES]; [213.212 SE/IT]; [213.213 IT]; [213.214 DE/FI]; [213.215 FR]; [213.216 DE/GB]; [213.217 DE]; [213.218 DE]; [213.219 GB]; [213.220 ES/DE]

[213.221 RU]; [213.222 NL]; [213.223 FR]; [213.224 BE]; [213.225 AT]; [213.226 BG/LT]; [213.227 ES]; [213.228 FR/PT]; [213.229 AT]; [213.230 SA/IT]; [213.231 PL]; [213.232 TR/CH]; [213.233 IT]; [213.234 ES/IT]; [213.235 GB]; [213.236 ES/NO]; [213.237 DK]; [213.238 SA]; [213.239 CH]; [213.240 YU/DE]

[213.241 PL]; [213.242 RU/SE]; [213.243 TR]; [213.244 FR/NL]; [213.245 FR]; [213.246 IT]; [213.247 EG]; [213.248 RU/TR]; [213.249 GR]; [213.250 SI/ES]; [213.251 NL]; [213.252 DE]; [213.253 GB]; [213.254 IT]; [213.255 IT/EG];