As per Relevance of the word security, we have this rfc below:
Network Working Group T.
Request for Comments: 1860
Category: Informational B.
October 1995
Variable Length Subnet Table For IPv
Status of this
This memo provides information for the Internet community. This
does not specify an Internet standard of any kind. Distribution
this memo is unlimited
This document itemizes the potential values for IPv4 subnets
Additional information is provided for Hex and Decmial values
classfull equivalents, and number of addresses available within
indicated block. We appreciate inputs from Bruce Pinsky (cisco)
Daniel Karrenberg (RIPE).
The following table lists the variable length subnets from 1 to 32,
the CIDR representation form and the Decmial equivalents
Mask value
Hex CIDR Decimal #of add
80.00.00.00 /1 128.0.0.0 2048 M 128
C0.00.00.00 /2 192.0.0.0 1024 M 64
E0.00.00.00 /3 224.0.0.0 512 M 32
F0.00.00.00 /4 240.0.0.0 256 M 16
F8.00.00.00 /5 248.0.0.0 128 M 8
FC.00.00.00 /6 252.0.0.0 64 M 4
FE.00.00.00 /7 254.0.0.0 32 M 2
FF.00.00.00 /8 255.0.0.0 16 M 1
FF.80.00.00 /9 255.128.0.0 8 M 128
FF.C0.00.00 /10 255.192.0.0 4 M 64
FF.E0.00.00 /11 255.224.0.0 2 M 32
FF.F0.00.00 /12 255.240.0.0 1024 K 16
FF.F8.00.00 /13 255.248.0.0 512 K 8
FF.FC.00.00 /14 255.252.0.0 256 K 4
FF.FE.00.00 /15 255.254.0.0 128 K 2
FF.FF.00.00 /16 255.255.0.0 64 K 1
FF.FF.80.00 /17 255.255.128.0 32 K 128
FF.FF.C0.00 /18 255.255.192.0 16 K 64
Pummill & Manning Informational [Page 1]
RFC 1860 Subnet Table October 1995
FF.FF.E0.00 /19 255.255.224.0 8 K 32
FF.FF.F0.00 /20 255.255.240.0 4 K 16
FF.FF.F8.00 /21 255.255.248.0 2 K 8
FF.FF.FC.00 /22 255.255.252.0 1 K 4
FF.FF.FE.00 /23 255.255.254.0 512 2
FF.FF.FF.00 /24 255.255.255.0 256 1
FF.FF.FF.80 /25 255.255.255.128 128
FF.FF.FF.C0 /26 255.255.255.192 64
FF.FF.FF.E0 /27 255.255.255.224 32
FF.FF.FF.F0 /28 255.255.255.240 16
FF.FF.FF.F8 /29 255.255.255.248 8
FF.FF.FF.FC /30 255.255.255.252 4
FF.FF.FF.FE /31 255.255.255.254 This space is not
FF.FF.FF.FF /32 255.255.255.255 This is a single host
The following tables illistrate some options for subnet/host
within selected block sizes
From a /16
# bits Mask Effective Subnets Effective
======== ===== ================= ===============
2 255.255.192.0 2 16382
3 255.255.224.0 6 8190
4 255.255.240.0 14 4094
5 255.255.248.0 30 2046
6 255.255.252.0 62 1022
7 255.255.254.0 126 510
8 255.255.255.0 254 254
9 255.255.255.128 510 126
10 255.255.255.192 1022 62
11 255.255.255.224 2046 30
12 255.255.255.240 4094 14
13 255.255.255.248 8190 6
14 255.255.255.252 16382 2
Pummill & Manning Informational [Page 2]
RFC 1860 Subnet Table October 1995
From a /24
# bits Mask Effective Subnets Effective
======== ===== ================= ===============
2 255.255.255.192 2 62
3 255.255.255.224 6 30
4 255.255.255.240 14 14
5 255.255.255.248 30 6
6 255.255.255.252 62 2
*Subnet all zeroes and all ones excluded
*Host all zeroes and all ones excluded
[1] Fuller, V., Li, T., Yu, J., and K. Varadhan, "Classless Inter
Domain Routing (CIDR): an Address Assignment and
Strategy", RFC 1519, BARRNet, cicso, Merit, OARnet,
1993.
Security
Security issues are not discussed in this memo
Authors'
Troy
EMail: trop@alantec.
Bill
Information Sciences
University of Southern
4676 Admiralty
Marina del Rey, CA 90292-6695
Phone: +1 310-822-1511 x387
Fax: +1 310-823-6714
EMail: bmanning@isi.
Pummill & Manning Informational [Page 3]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
RFC documents can be found at I.E.T.F.
Relevance System Copyright © 2002 Spectrum WorldResearch
other technical nosh by ServerMasters Corporation
collaboration of BobX
