Novell LINUX ENTERPRISE SERVER 11 - ADMINISTRATION Administration Manual page 218

Example 17.2 Linking IP Addresses to the Netmask
IP address (192.168.0.20):
Netmask
---------------------------------------------------------------
Result of the link:
In the decimal system:
IP address (213.95.15.200): 11010101 10111111 00001111 11001000
Netmask
---------------------------------------------------------------
Result of the link:
In the decimal system:
To give another example: all machines connected with the same ethernet cable are
usually located in the same subnetwork and are directly accessible. Even when the
subnet is physically divided by switches or bridges, these hosts can still be reached di-
rectly.
IP addresses outside the local subnet can only be reached if a gateway is configured
for the target network. In the most common case, there is only one gateway that handles
all traffic that is external. However, it is also possible to configure several gateways
for different subnets.
If a gateway has been configured, all external IP packets are sent to the appropriate
gateway. This gateway then attempts to forward the packets in the same manner—from
host to host—until it reaches the destination host or the packet's TTL (time to live) ex-
pires.
Table 17.2
Address Type
Base Network Ad-
dress
Broadcast Address
204 Administration Guide
11000000 10101000 00000000 00010100
(255.255.255.0): 11111111 11111111 11111111 00000000
11000000 10101000 00000000 00000000
(255.255.255.0): 11111111 11111111 11111111 00000000
11010101 10111111 00001111 00000000
Specific Addresses
Description
This is the netmask AND any address in the network, as shown
in Example 17.2, "Linking IP Addresses to the Netmask"
(page 204) under Result. This address cannot be assigned to
any hosts.
This basically says, "Access all hosts in this subnetwork." To
generate this, the netmask is inverted in binary form and linked
to the base network address with a logical OR. The above ex-
192. 168.
213. 95.
0. 0
15. 0