Appendix E IP Addresses and Subnetting
P-793H User’s Guide
392
Subnetting
You can use subnetting to divide one network into multiple sub-networks. In the following
example a network administrator creates two sub-networks to isolate a group of servers from
the rest of the company network for security reasons.
In this example, the company network address is 192.168.1.0. The first three octets of the
address (192.168.1) are the network number, and the remaining octet is the host ID, allowing a
maximum of 2
8
– 2 or 254 possible hosts.
The following figure shows the company network before subnetting.
Figure 279
Subnetting Example: Before Subnetting
You can “borrow” one of the host ID bits to divide the network 192.168.1.0 into two separate
sub-networks. The subnet mask is now 25 bits (255.255.255.128 or /25).
The “borrowed” host ID bit can have a value of either 0 or 1, allowing two subnets;
192.168.1.0 /25 and 192.168.1.128 /25.
The following figure shows the company network after subnetting. There are now two sub-
networks,
A
and
B
.
255.255.255.192
/26
1100 0000
192
255.255.255.224
/27
1110 0000
224
255.255.255.240
/28
1111 0000
240
255.255.255.248
/29
1111 1000
248
255.255.255.252
/30
1111 1100
252
Table 141
Alternative Subnet Mask Notation (continued)
SUBNET MASK
ALTERNATIVE
NOTATION
LAST OCTET
(BINARY)
LAST OCTET
(DECIMAL)
Summary of Contents for G.SHDSL.bis 4-port Security Gateway P-793H
Page 2: ......
Page 7: ...Safety Warnings P 793H User s Guide 7 This product is recyclable Dispose of it properly ...
Page 8: ...Safety Warnings P 793H User s Guide 8 ...
Page 30: ...List of Figures P 793H User s Guide 30 ...
Page 36: ...List of Tables P 793H User s Guide 36 ...
Page 38: ...38 ...
Page 68: ...Chapter 4 Point to 2 point Configuration P 793H User s Guide 68 ...
Page 70: ...70 ...
Page 114: ...Chapter 7 Network Address Translation NAT Screens P 793H User s Guide 114 ...
Page 116: ...116 ...
Page 152: ...Chapter 10 Content Filtering P 793H User s Guide 152 ...
Page 180: ...Chapter 12 Static Route P 793H User s Guide 180 ...
Page 194: ...Chapter 14 Dynamic DNS Setup P 793H User s Guide 194 ...
Page 216: ...Chapter 16 Universal Plug and Play UPnP P 793H User s Guide 216 ...
Page 217: ...217 PART IV Maintenance System 219 Logs 225 Tools 229 Diagnostic 235 ...
Page 218: ...218 ...
Page 224: ...Chapter 17 System P 793H User s Guide 224 ...
Page 234: ...Chapter 19 Tools P 793H User s Guide 234 ...
Page 238: ...238 ...
Page 244: ...Chapter 21 Introducing the SMT P 793H User s Guide 244 ...
Page 248: ...Chapter 22 General Setup P 793H User s Guide 248 ...
Page 256: ...Chapter 23 WAN Setup P 793H User s Guide 256 ...
Page 262: ...Chapter 24 LAN Setup P 793H User s Guide 262 ...
Page 278: ...Chapter 27 Static Route Setup P 793H User s Guide 278 ...
Page 308: ...Chapter 30 Filter Configuration P 793H User s Guide 308 ...
Page 310: ...Chapter 31 SNMP Configuration P 793H User s Guide 310 ...
Page 312: ...Chapter 32 System Password P 793H User s Guide 312 ...
Page 322: ...Chapter 33 System Information Diagnosis P 793H User s Guide 322 ...
Page 352: ...Chapter 37 Schedule Setup P 793H User s Guide 352 ...
Page 360: ...360 ...
Page 366: ...Appendix B Wall mounting Instructions P 793H User s Guide 366 ...
Page 400: ...Appendix F IP Address Assignment Conflicts P 793H User s Guide 400 ...
Page 404: ...Appendix G Common Services P 793H User s Guide 404 ...
Page 432: ...Appendix K Legal Information P 793H User s Guide 432 ...
Page 443: ...Index P 793H User s Guide 443 ...
Page 444: ...Index P 793H User s Guide 444 ...