Using Subnet Zero - Cisco Catalyst 9500 series Configuration Manual

Configuring IP Unicast Routing
Step 6
Step 7
Step 8
Step 9
Step 10
Step 11

Using Subnet Zero

Subnetting with a subnet address of zero is strongly discouraged because of the problems that can arise if a
network and a subnet have the same addresses. For example, if network 131.108.0.0 is subnetted as
255.255.255.0, subnet zero would be written as 131.108.0.0, which is the same as the network address.
You can use the all ones subnet (131.108.255.0) and even though it is discouraged, you can enable the use of
subnet zero if you need the entire subnet space for your IP address.
Use the no ip subnet-zero global configuration command to restore the default and disable the use of subnet
zero.
Command or Action
no shutdown
Example:
Device(config-if)# no shutdown
end
Example:
Device(config)# end
show ip route
Example:
Device# show ip route
show ip interface [interface-id]
Example:
Device# show ip interface gigabitethernet
1/0/1
show running-config
Example:
Device# show running-config
copy running-config startup-config
Example:
Device# copy running-config
startup-config
Routing Configuration Guide, Cisco IOS XE Everest 16.6.x (Catalyst 9500 Switches)
Assigning IP Addresses to Network Interfaces
Purpose
Enables the physical interface.
Returns to privileged EXEC mode.
Verifies your entries.
Verifies your entries.
Verifies your entries.
(Optional) Saves your entries in the
configuration file.
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