CIDR
/30
/29
/28
/27
/26
/25
/24
/23
/22
/21
/20
/19
/18
/17
/16
Adresses
4
8
16
32
64
128
256
512
1024
2048
4096
8192
16384
32768
65536
Hosts
2
6
14
30
62
126
254
510
1022
2046
4094
8190
16382
32766
65534
Subnet Mask
255.255.255.252
255.255.255.248
255.255.255.240
255.255.255.224
255.255.255.192
255.255.255.128
255.255.255.0
255.255.254.0
255.255.252.0
255.255.248.0
255.255.240.0
255.255.224.0
255.255.192.0
255.255.128.0
255.255.0.0
# of a Class C
1/64
1/32
1/16
1/8
1/4
1/2
1
2
4
8
16
32
64
128
256
OSI Model Quick Reference
Data unit
Layer
Function
7. Application
Netw ork process to application
6. Presentation
Data representation, encryption and decryption,
convert machine dependent data to machine
independent data
5. Session
Interhost communication, managing sessions
betw een applications
Segments
4. Transport
Reliable delivery of packets betw een points on a
netw ork.
Packet/Datagram
3. Netw ork
Addressing, routing and (not necessarily
reliable) delivery of datagrams betw een points
on a netw ork.
Bit/Frame
2. Data link
A reliable direct point-to-point data connection.
Bit
1. Physical
A (not necessarily reliable) direct point-to-point
data connection.
Data
Hos t Layer s
Media
Layer s
http://www.binaryheartbeat.blogspot.com
CIDR
/25
Net Address
0
128
CIDR
/26
Net Address
0
64
128
192
CIDR
/27
Net Address
0
32
64
96
128
160
192
224
CIDR
/28
Net Address
0
16
32
48
64
80
96
112
128
144
160
176
192
208
224
240
Subnets
2
IP Range
1
129
to
to
Subnets
4
IP Range
1
65
129
193
to
to
to
to
Subnets
8
IP Range
1
33
65
97
129
161
193
225
to
to
to
to
to
to
to
to
Subnets
16
IP Range
1
17
33
49
65
81
97
113
129
145
161
177
193
209
225
241
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
Hosts/Subnet
126
Broadcast
128
254
127
255
Hosts/Subnet
62
Broadcast
62
126
190
254
63
127
191
255
Hosts/Subnet
30
Broadcast
30
62
94
126
158
190
222
254
31
63
95
127
159
191
223
255
Hosts/Subnet
14
Broadcast
14
30
46
62
78
94
110
126
142
158
174
190
206
222
238
254
15
31
47
63
79
95
111
127
143
159
175
191
207
223
239
255
CIDR
/29
Net Address
0
8
16
24
32
40
48
56
64
72
80
88
96
104
112
120
128
136
144
152
160
168
176
184
192
200
208
216
224
232
240
248
Subnets
32
IP Range
1
9
17
25
33
41
49
57
65
73
81
89
97
105
113
121
129
137
145
153
161
169
177
185
193
201
209
217
225
233
241
249
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
Hosts/Subnet
6
Broadcast
6
14
22
30
38
46
54
62
70
78
86
94
102
110
118
126
134
142
150
158
166
174
182
190
198
206
214
222
230
238
246
254
7
15
23
31
39
47
55
63
71
79
87
95
103
111
119
127
135
143
151
159
167
175
183
191
199
207
215
223
231
239
247
255
CIDR
/30
Net Address
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
60
64
68
72
76
80
84
88
92
96
100
104
108
112
116
120
124
Subnets
64
IP Range
1
5
9
13
17
21
25
29
33
37
41
45
49
53
57
61
65
69
73
77
81
85
89
93
97
101
105
109
113
117
121
125
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
Hosts/Subnet
2
Broadcast
2
6
10
14
18
22
26
30
34
38
42
46
50
54
58
62
66
70
74
78
82
86
90
94
98
102
106
110
114
118
122
126
http://www.binaryheartbeat.blogspot.com
3
7
11
15
19
23
27
31
35
39
43
47
51
55
59
63
67
71
75
79
83
87
91
95
99
103
107
111
115
119
123
127
/30 Continued
128
132
136
140
144
148
152
156
160
164
168
172
176
180
184
188
192
196
200
204
208
212
216
220
224
228
232
236
240
244
248
252
129
133
137
141
145
149
153
157
161
165
169
173
177
181
185
189
193
197
201
205
209
213
217
221
225
229
233
237
241
245
249
253
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
to
130
134
138
142
146
150
154
158
162
166
170
174
178
182
186
190
194
198
202
206
210
214
218
222
226
230
234
238
242
246
250
254
131
135
139
143
147
151
155
159
163
167
171
175
179
183
187
191
195
199
203
207
211
215
219
223
227
231
235
239
243
247
251
255
Data unit
OSI Model
Layer
Function
7. Application
Network process to application
6. Presentation
Data representation, encryption and decryption,
convert machine dependent data to machine
independent data
5. Session
Interhost communication, managing sessions
between applications
Segments
4. Transport
Reliable delivery of packets between points on a
network.
Packet/Datagram
3. Network
Addressing, routing and (not necessarily reliable)
delivery of datagrams between points on a
network.
2. Data link
A reliable direct point-to-point data connection.
1. Physical
A (not necessarily reliable) direct point-to-point
data connection.
Data
Host Layers
Media Layers Bit/Frame
Bit