Class A Address Guide
|
|||||
CIDR
|
Bits Borrow
|
Subnet Mask
|
# of Subnets
|
# of Hosts
|
Usable # of Hosts
|
/8
|
0
|
255.0.0.0
|
1
|
16,777,216
|
16,777,214
|
/9
|
1
|
255.128.0.0
|
2
|
8,388,608
|
8,388,606
|
/10
|
2
|
255.192.0.0
|
4
|
4,194,304
|
4,194,302
|
/11
|
3
|
255.224.0.0
|
8
|
2,097,152
|
2,097,150
|
/12
|
4
|
255.240.0.0
|
16
|
1,048,576
|
1,048,574
|
/13
|
5
|
255.248.0.0
|
32
|
524,288
|
524,2846
|
/14
|
6
|
255.252.0.0
|
64
|
262,144
|
262,142
|
/15
|
7
|
255.254.0.0
|
128
|
131,072
|
131,070
|
/16
|
8
|
255.255.0.0
|
256
|
65,536
|
65,534
|
/17
|
9
|
255.255.128.0
|
512
|
32,768
|
32,766
|
/18
|
10
|
255.255.192.0
|
1,024
|
16,384
|
16,382
|
/19
|
11
|
255.255.224.0
|
2,048
|
8,192
|
8,190
|
/20
|
12
|
255.255.240.0
|
4,096
|
4,096
|
4,094
|
/21
|
13
|
255.255.248.0
|
8,192
|
2,048
|
2,046
|
/22
|
14
|
255.255.252.0
|
16,384
|
1,024
|
1,022
|
/23
|
15
|
255.255.254.0
|
32,768
|
512
|
510
|
/24
|
16
|
255.255.255.0
|
65,536
|
256
|
254
|
/25
|
17
|
255.255.255.128
|
131,072
|
128
|
126
|
/26
|
18
|
255.255.255.192
|
262,144
|
64
|
62
|
/27
|
19
|
255.255.255.224
|
524,288
|
32
|
30
|
/28
|
20
|
255.255.255.240
|
1,048,576
|
16
|
14
|
/29
|
21
|
255.255.255.248
|
2,097,152
|
8
|
6
|
/30
|
22 22
|
255.255.255.252
|
4,194,304
|
4
|
2
|
Class B Address Guide
|
|||||
CIDR
|
Bits Borrow
|
Subnet Mask
|
# of Subnets
|
# of Hosts
|
Usable # of Hosts
|
/16
|
0
|
255.255.0.0
|
1
|
65,536
|
65,534
|
/17
|
1
|
255.255.128.0
|
2
|
32,768
|
32,766
|
/18
|
2
|
255.255.192.0
|
4
|
16,384
|
16,382
|
/19
|
3
|
255.255.224.0
|
8
|
8,192
|
8,190
|
/20
|
4
|
255.255.240.0
|
16
|
4,096
|
4,094
|
/21
|
5
|
255.255.248.0
|
32
|
2,048
|
2,046
|
/22
|
6
|
255.255.252.0
|
64
|
1,024
|
1,022
|
/23
|
7
|
255.255.254.0
|
128
|
512
|
510
|
/24
|
8
|
255.255.255.0
|
256
|
256
|
254
|
/25
|
9
|
255.255.255.128
|
512
|
128
|
126
|
/26
|
10
|
255.255.255.192
|
1,024
|
64
|
62
|
/27
|
11
|
255.255.255.224
|
2,048
|
32
|
30
|
/28
|
12
|
255.255.255.240
|
4,096
|
16
|
14
|
/29
|
13
|
255.255.255.248
|
8,192
|
8
|
6
|
/30
|
14
|
255.255.255.252
|
16,384
|
4
|
2
|
Class C Address Guide
|
|||||
CIDR
|
Bits Borrow
|
Subnet Mask
|
# of Subnets
|
# of Hosts
|
Usable # of Hosts
|
/24
|
0
|
255.255.255.0
|
1
|
256
|
254
|
/25
|
1
|
255.255.255.128
|
2
|
128
|
126
|
/26
|
2
|
255.255.255.192
|
4
|
64
|
62
|
/27
|
3
|
255.255.255.224
|
8
|
32
|
30
|
/28
|
4
|
255.255.255.240
|
16
|
16
|
14
|
/29
|
5
|
255.255.255.248
|
32
|
8
|
6
|
/30
|
6
|
255.255.255.252
|
64
|
4
|
2
|
Figure IPv 4 Special Use IP Addresses
Subnetting
2^7 |2^6|2^5|2^4|2^3|2^2|2^1|2
128 |64 |32|16|8|4|2|1|
Network= 2^N where N=Network bits
Hosts = 2^H - 2 Where H is the host bits
Classfull Networks
A 0-191.0.0.0 255.0.0.0
B 192-223.0.0.0 255.255.0.0
C 224-
D
E
Subnetting is taking a large network and dividing it into smaller network
Network: all host bits set to Zero
Broadcast: All host bits set to one
150.50.0.0
150.50.255.255
If you have a class c network 192.168.3.0/24 and you need 4 networks
class bits = 8 bits 2^8=256 so each group will be 256/4 = 64
Network = 2^N =4
N=2 so you need 2 bits
255.255.255.11000000
Host bits
2^6 -2 = 64-2 =62 Hosts
Networks
0-63
64-127
128-191
192-255
Subnetting
2^7 |2^6|2^5|2^4|2^3|2^2|2^1|2
128 |64 |32|16|8|4|2|1|
Network= 2^N where N=Network bits
Hosts = 2^H - 2 Where H is the host bits
Classfull Networks
A 0-191.0.0.0 255.0.0.0
B 192-223.0.0.0 255.255.0.0
C 224-
D
E
subnetting is taking a large network and dividing it into smaller network
Network: all host bits set to Zero
Broadcast: All host bits set to one
150.50.0.0
150.50.255.255
If you have a class c network 192.168.3.0/24 and you need 4 networks
class bits = 8 bits 2^8=256 so each group will be 256/4 = 64
Network = 2^N =4
N=2 so you need 2 bits
255.255.255.11000000
Host bits
2^6 -2 = 64-2 =62 Hosts
Networks
0-63
64-127
128-191
192-255
2^7 |2^6|2^5|2^4|2^3|2^2|2^1|2
128 |64 |32|16|8|4|2|1|
Network= 2^N where N=Network bits
Hosts = 2^H - 2 Where H is the host bits
Classfull Networks
A 0-191.0.0.0 255.0.0.0
B 192-223.0.0.0 255.255.0.0
C 224-
D
E
Subnetting is taking a large network and dividing it into smaller network
Network: all host bits set to Zero
Broadcast: All host bits set to one
150.50.0.0
150.50.255.255
If you have a class c network 192.168.3.0/24 and you need 4 networks
class bits = 8 bits 2^8=256 so each group will be 256/4 = 64
Network = 2^N =4
N=2 so you need 2 bits
255.255.255.11000000
Host bits
2^6 -2 = 64-2 =62 Hosts
Networks
0-63
64-127
128-191
192-255
Subnetting
2^7 |2^6|2^5|2^4|2^3|2^2|2^1|2
128 |64 |32|16|8|4|2|1|
Network= 2^N where N=Network bits
Hosts = 2^H - 2 Where H is the host bits
Classfull Networks
A 0-191.0.0.0 255.0.0.0
B 192-223.0.0.0 255.255.0.0
C 224-
D
E
subnetting is taking a large network and dividing it into smaller network
Network: all host bits set to Zero
Broadcast: All host bits set to one
150.50.0.0
150.50.255.255
If you have a class c network 192.168.3.0/24 and you need 4 networks
class bits = 8 bits 2^8=256 so each group will be 256/4 = 64
Network = 2^N =4
N=2 so you need 2 bits
255.255.255.11000000
Host bits
2^6 -2 = 64-2 =62 Hosts
Networks
0-63
64-127
128-191
192-255
| /25 -- 2 Subnets -- 126 Hosts/Subnet | ||
| Network # | IP Range | Broadcast |
| 0 | .1-.126 | 0.127 |
| 0.128 | .129-.254 | 0.255 |
| /26 -- 4 Subnets -- 62 Hosts/Subnet | ||
| Network # | IP Range | Broadcast |
| 0 | .1-.62 | 0.63 |
| 0.64 | .65-.126 | 0.127 |
| 0.128 | .129-.190 | 0.191 |
| 0.192 | .193-.254 | 0.255 |
| /27 -- 8 Subnets -- 30 Hosts/Subnet | ||
| Network # | IP Range | Broadcast |
| 0 | .1-.30 | 0.31 |
| 0.32 | .33-.62 | 0.63 |
| 0.64 | .65-.94 | 0.95 |
| 0.96 | .97-.126 | 0.127 |
| 0.128 | .129-.158 | 0.159 |
| 0.16 | .161-.190 | 0.191 |
| 0.192 | .193-.222 | 0.223 |
| 0.224 | .225-.254 | 0.255 |
| /28 -- 16 Subnets -- 14 Hosts/Subnet | ||
| Network # | IP Range | Broadcast |
| 0 | .1-.14 | 0.15 |
| 0.16 | .17-.30 | 0.31 |
| 0.32 | .33-.46 | 0.47 |
| 0.48 | .49-.62 | 0.63 |
| 0.64 | .65-.78 | 0.79 |
| 0.8 | .81-.94 | 0.95 |
| 0.96 | .97-.110 | 0.111 |
| 0.112 | .113-.126 | 0.127 |
| 0.128 | .129-.142 | 0.143 |
| 0.144 | .145-.158 | 0.159 |
| 0.16 | .161-.174 | 0.175 |
| 0.176 | .177-.190 | 0.191 |
| 0.192 | .193-.206 | 0.207 |
| 0.208 | .209-.222 | 0.223 |
| 0.224 | .225-.238 | 0.239 |
| 0.24 | .241-.254 | 0.255 |
| /29 -- 32 Subnets -- 6 Hosts/Subnet | ||
| Network # | IP Range | Broadcast |
| 0 | .1-.6 | 0.7 |
| 0.8 | .9-.14 | 0.15 |
| 0.16 | .17-.22 | 0.23 |
| 0.24 | .25-.30 | 0.31 |
| 0.32 | .33-.38 | 0.39 |
| 0.4 | .41-.46 | 0.47 |
| 0.48 | .49-.54 | 0.55 |
| 0.56 | .57-.62 | 0.63 |
| 0.64 | .65-.70 | 0.71 |
| 0.72 | .73-.78 | 0.79 |
| 0.8 | .81-.86 | 0.87 |
| 0.88 | .89-.94 | 0.95 |
| 0.96 | .97-.102 | 0.103 |
| 0.104 | .105-.110 | 0.111 |
| 0.112 | .113-.118 | 0.119 |
| 0.12 | .121-.126 | 0.127 |
| 0.128 | .129-.134 | 0.135 |
| 0.136 | .137-.142 | 0.143 |
| 0.144 | .145-.150 | 0.151 |
| 0.152 | .153-.158 | 0.159 |
| 0.16 | .161-.166 | 0.167 |
| 0.168 | .169-.174 | 0.175 |
| 0.176 | .177-.182 | 0.183 |
| 0.184 | .185-.190 | 0.191 |
| 0.192 | .193-.198 | 0.199 |
| 0.2 | .201-.206 | 0.207 |
| 0.208 | .209-.214 | 0.215 |
| 0.216 | .217-.222 | 0.223 |
| 0.224 | .225-.230 | 0.231 |
| 0.232 | .233-.238 | 0.239 |
| 0.24 | .241-.246 | 0.247 |
| 0.248 | .249-.254 | 0.255 |
| /30 -- 64 Subnets -- 2 Hosts/Subnet | ||
| Network # | IP Range | Broadcast |
| 0 | .1-.2 | 0.3 |
| 0.4 | .5-.6 | 0.7 |
| 0.8 | .9-.10 | 0.11 |
| 0.12 | .13-.14 | 0.15 |
| 0.16 | .17-.18 | 0.19 |
| 0.2 | .21-.22 | 0.23 |
| 0.24 | .25-.26 | 0.27 |
| 0.28 | .29-.30 | 0.31 |
| 0.32 | .33-.34 | 0.35 |
| 0.36 | .37-.38 | 0.39 |
| 0.4 | .41-.42 | 0.43 |
| 0.44 | .45-.46 | 0.47 |
| 0.48 | .49-.50 | 0.51 |
| 0.52 | .53-.54 | 0.55 |
| 0.56 | .57-.58 | 0.59 |
| 0.6 | .61-.62 | 0.63 |
| 0.64 | .65-.66 | 0.67 |
| 0.68 | .69-.70 | 0.71 |
| 0.72 | .73-.74 | 0.75 |
| 0.76 | .77-.78 | 0.79 |
| 0.8 | .81-.82 | 0.83 |
| 0.84 | .85-.86 | 0.87 |
| 0.88 | .89-.90 | 0.91 |
| 0.92 | .93-.94 | 0.95 |
| 0.96 | .97-.98 | 0.99 |
| 0.1 | .101-.102 | 0.103 |
| 0.104 | .105-.106 | 0.107 |
| 0.108 | .109-.110 | 0.111 |
| 0.112 | .113-.114 | 0.115 |
| 0.116 | .117-.118 | 0.119 |
| 0.12 | .121-.122 | 0.123 |
| 0.124 | .125-.126 | 0.127 |
| 0.128 | .129-.130 | 0.131 |
| 0.132 | .133-.134 | 0.135 |
| 0.136 | .137-.138 | 0.139 |
| 0.14 | .141-.142 | 0.143 |
| 0.144 | .145-.146 | 0.147 |
| 0.148 | .149-.150 | 0.151 |
| 0.152 | .153-.154 | 0.155 |
| 0.156 | .157-.158 | 0.159 |
| 0.16 | .161-.162 | 0.163 |
| 0.164 | .165-.166 | 0.167 |
| 0.168 | .169-.170 | 0.171 |
| 0.172 | .173-.174 | 0.175 |
| 0.176 | .177-.178 | 0.179 |
| 0.18 | .181-.182 | 0.183 |
| 0.184 | .185-.186 | 0.187 |
| 0.188 | .189-.190 | 0.191 |
| 0.192 | .193-.194 | 0.195 |
| 0.196 | .197-.198 | 0.199 |
| 0.2 | .201-.202 | 0.203 |
| 0.204 | .205-.206 | 0.207 |
| 0.208 | .209-.210 | 0.211 |
| 0.212 | .213-.214 | 0.215 |
| 0.216 | .217-.218 | 0.219 |
| 0.22 | .221-.222 | 0.223 |
| 0.224 | .225-.226 | 0.227 |
| 0.228 | .229-.230 | 0.231 |
| 0.232 | .233-.234 | 0.235 |
| 0.236 | .237-.238 | 0.239 |
| 0.24 | .241-.242 | 0.243 |
| 0.244 | .245-.246 | 0.247 |
| 0.248 | .249-.250 | 0.251 |
| 0.252 | .253-.254 | 0.255 |
Netmask Netmask (binary) CIDR Notes
_____________________________________________________________________________
255.255.255.255 11111111.11111111.11111111.11111111 /32 Host (single addr)
255.255.255.254 11111111.11111111.11111111.11111110 /31 Unuseable
255.255.255.252 11111111.11111111.11111111.11111100 /30 2 useable
255.255.255.248 11111111.11111111.11111111.11111000 /29 6 useable
255.255.255.240 11111111.11111111.11111111.11110000 /28 14 useable
255.255.255.224 11111111.11111111.11111111.11100000 /27 30 useable
255.255.255.192 11111111.11111111.11111111.11000000 /26 62 useable
255.255.255.128 11111111.11111111.11111111.10000000 /25 126 useable
255.255.255.0 11111111.11111111.11111111.00000000 /24 "Class C" 254 useable
255.255.254.0 11111111.11111111.11111110.00000000 /23 2 Class C's
255.255.252.0 11111111.11111111.11111100.00000000 /22 4 Class C's
255.255.248.0 11111111.11111111.11111000.00000000 /21 8 Class C's
255.255.240.0 11111111.11111111.11110000.00000000 /20 16 Class C's
255.255.224.0 11111111.11111111.11100000.00000000 /19 32 Class C's
255.255.192.0 11111111.11111111.11000000.00000000 /18 64 Class C's
255.255.128.0 11111111.11111111.10000000.00000000 /17 128 Class C's
255.255.0.0 11111111.11111111.00000000.00000000 /16 "Class B"
255.254.0.0 11111111.11111110.00000000.00000000 /15 2 Class B's
255.252.0.0 11111111.11111100.00000000.00000000 /14 4 Class B's
255.248.0.0 11111111.11111000.00000000.00000000 /13 8 Class B's
255.240.0.0 11111111.11110000.00000000.00000000 /12 16 Class B's
255.224.0.0 11111111.11100000.00000000.00000000 /11 32 Class B's
255.192.0.0 11111111.11000000.00000000.00000000 /10 64 Class B's
255.128.0.0 11111111.10000000.00000000.00000000 /9 128 Class B's
255.0.0.0 11111111.00000000.00000000.00000000 /8 "Class A"
254.0.0.0 11111110.00000000.00000000.00000000 /7
252.0.0.0 11111100.00000000.00000000.00000000 /6
248.0.0.0 11111000.00000000.00000000.00000000 /5
240.0.0.0 11110000.00000000.00000000.00000000 /4
224.0.0.0 11100000.00000000.00000000.00000000 /3
192.0.0.0 11000000.00000000.00000000.00000000 /2
128.0.0.0 10000000.00000000.00000000.00000000 /1
0.0.0.0 00000000.00000000.00000000.00000000 /0 IP space
For wildcard netmasks (aka reverse netmasks), subtract each octet of a standard netmask from 255.
Example 1: 255.255.255.0 becomes 0.0.0.255
Example 2: 255.255.252.0 becomes 0.0.3.255
###############################################################################
Net Host Total
Net Addr Addr Addr Number
Class Range NetMask Bits Bits of hosts
----------------------------------------------------------
A 0-127 255.0.0.0 8 24 16777216 (i.e. 114.0.0.0)
B 128-191 255.255.0.0 16 16 65536 (i.e. 150.0.0.0)
C 192-254 255.255.255.0 24 8 256 (i.e. 199.0.0.0)
D 224-239 (multicast)
E 240-255 (reserved)
F 208-215 255.255.255.240 28 4 16
G 216/8 ARIN - North America
G 217/8 RIPE NCC - Europe
G 218-219/8 APNIC
H 220-221 255.255.255.248 29 3 8 (reserved)
K 222-223 255.255.255.254 31 1 2 (reserved)
(ref: RFC1375 & http://www.iana.org/assignments/ipv4-address-space )
( http://www.iana.org/numbers.htm )
The current list of special use prefixes:
0.0.0.0/8
127.0.0.0/8
192.0.2.0/24
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
169.254.0.0/16
all D/E space
(ref: RFC1918 http://www.rfc-editor.org/rfc/rfc1918.txt )
( or ftp://ftp.isi.edu/in-notes/rfc1918.txt )
(rfc search: http://www.rfc-editor.org/rfcsearch.html )
( http://www.ietf.org/ietf/1id-abstracts.txt )
( http://www.ietf.org/shadow.html )
Martians: (updates at: www.iana.org/assignments/ipv4-address-space )
no ip source-route
access-list 100 deny ip host 0.0.0.0 any
deny ip 0.0.0.0 0.255.255.255 any log ! antispoof
deny ip 0.0.0.0 0.255.255.255 0.0.0.0 255.255.255.255 ! antispoof
deny ip any 255.255.255.128 0.0.0.127 ! antispoof
deny ip host 0.0.0.0 any log ! antispoof
deny ip host [router intf] [router intf] ! antispoof
deny ip xxx.xxx.xxx.0 0.0.0.255 any log ! lan area
deny ip 0/8 0.255.255.255 any log ! IANA - Reserved
deny ip 1/8 0.255.255.255 any log ! IANA - Reserved
deny ip 2/8 0.255.255.255 any log ! IANA - Reserved
deny ip 5/8 0.255.255.255 any log ! IANA - Reserved
deny ip 7/8 0.255.255.255 any log ! IANA - Reserved
deny ip 10.0.0.0 0.255.255.255 any log ! IANA - Private Use
deny ip 23/8 0.255.255.255 any log ! IANA - Reserved
deny ip 27/8 0.255.255.255 any log ! IANA - Reserved
deny ip 31/8 0.255.255.255 any log ! IANA - Reserved
deny ip 36-37/8 0.255.255.255 any log ! IANA - Reserved
deny ip 39/8 0.255.255.255 any log ! IANA - Reserved
deny ip 41-42/8 0.255.255.255 any log ! IANA - Reserved
deny ip 50/8 0.255.255.255 any log ! IANA - Reserved
deny ip 58-60/8 0.255.255.255 any log ! IANA - Reserved
deny ip 69-79/8 0.255.255.255 any log ! IANA - Reserved
deny ip 82-95/8 0.255.255.255 any log ! IANA - Reserved
deny ip 96-126/8 0.255.255.255 any log ! IANA - Reserved
deny ip 127/8 0.255.255.255 any log ! IANA - Reserved
deny ip 169.254.0.0 0.0.255.255 any log ! link-local network
deny ip 172.16.0.0 0.15.255.255 any log ! reserved
deny ip 192.168.0.0 0.0.255.255 any log ! reserved
deny ip 192.0.2.0 0.0.0.255 any log ! test network
deny ip 197/8 0.255.255.255 any log ! IANA - Reserved
deny ip 220/8 0.255.255.255 any log ! IANA - Reserved
deny ip 222-223/8 0.255.255.255 any log ! IANA - Reserved
deny ip 224.0.0.0 31.255.255.255 any log ! multicast
deny ip 224.0.0.0 15.255.255.255 any log ! unless MBGP-learned routes
deny ip 224-239/8 0.255.255.255 any log ! IANA - Multicast
deny ip 240-255/8 0.255.255.255 any log ! IANA - Reserved
filtered source addresses
0/8 ! broadcast
10/8 ! RFC 1918 private
127/8 ! loopback
169.254.0/16 ! link local
172.16.0.0/12 ! RFC 1918 private
192.0.2.0/24 ! TEST-NET
192.168.0/16 ! RFC 1918 private
224.0.0.0/4 ! class D multicast
240.0.0.0/5 ! class E reserved
248.0.0.0/5 ! reserved
255.255.255.255/32 ! broadcast
ARIN administrated blocks: (http://www.arin.net/regserv/IPStats.html)
24.0.0.0/8 (portions of)
63.0.0.0/8
64.0.0.0/8
65.0.0.0/8
66.0.0.0/8
196.0.0.0/8
198.0.0.0/8
199.0.0.0/8
200.0.0.0/8
204.0.0.0/8
205.0.0.0/8
206.0.0.0/8
207.0.0.0/8
208.0.0.0/8
209.0.0.0/8
216.0.0.0/8
########################################################################
well known ports: (rfc1700.txt)
www.iana.org/assignments/port-numbers
protocol numbers:
www.iana.org/assignments/protocol-numbers
www.iana.org/numbers.htm
Protocol Protocol Number
-------- ---------------
ICMP 1
IGRP 9
EIGRP 88
OSPF 89
IPv6 41
GRE 47
IPX in IP 111
L2TP 115
