Administrator's Guide

Appendix C. Lists of Reserved Ports, ICMP Types and Codes, and Internet Protocols
(130.234.250.64-130.234.250.95).
Class IP in-
tervals
0 0-255
1 0-127 128-255
2 0-63 64-127 128-191 192-255
3 0-31 32-63 64-95 96-127 128-159 160-191 192-223 224-255
4 0-15 16-31 32-47 48-63 64-79 80-95 96-111 112-127
128-143 144-159 160-175 176-191 192-207 208-223 224-239 240-255
5 0-7 8-15 16-23 24-31 32-39 40-47 48-55 56-63
64-71 72-79 80-87 88-95 96-103 104-111 112-119 120-127
128-135 136-143 144-151 152-159 160-167 168-175 176-183 184-191
192-199 200-207 208-215 216-223 224-231 232-239 240-247 248-255
6 0-3 4-7 8-11 12-15 16-19 20-23 24-27 28-31
32-35 36-39 40-43 44-47 48-51 52-55 56-59 60-63
64-67 68-71 72-75 76-79 80-83 84-87 88-91 92-95
96-99 100-103 104-107 108-111 112-115 116-119 120-123 124-127
128-131 132-135 136-139 140-143 144-147 148-151 152-155 156-159
160-163 164-167 168-171 172-175 176-179 180-183 184-187 188-191
192-195 196-199 200-203 204-207 208-211 212-215 216-219 220-223
224-227 228-231 232-235 236-239 240-243 244-247 248-251 252-255
7 0-1 2-3 4-5 6-7 8-9 10-11 ... 254-255
8 0 1 2 3 4 5 ... 255
You could have a large network, for example 130.234.128.0/18, which is interpreted from
the tables as all IP addresses from 130.234.128.0 to 130.234.191.255, inclusive (18 is in
class no. 2, giving an IP interval of 128-191). N.B.: The netmask only reaches the third byte,
which means that all IP addresses in byte 4 are available.
Reserved IP addresses
The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks
of the IP address space for private internets (see also RFC 1918):
• 10.0.0.0 - 10.255.255.255 (10/8)
• 172.16.0.0 - 172.31.255.255 (172.16/12)
• 192.168.0.0 - 192.168.255.255 (192.168/16)
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