Disabling Classless Routing - Cisco Catalyst 9500 series Configuration Manual

Assigning IP Addresses to Network Interfaces
Procedure
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6

Disabling Classless Routing

To prevent the Device from forwarding packets destined for unrecognized subnets to the best supernet route
possible, you can disable classless routing behavior.
Routing Configuration Guide, Cisco IOS XE Everest 16.6.x (Catalyst 9500 Switches)
62
Command or Action
enable
Example:
Device> enable
configure terminal
Example:
Device# configure terminal
ip subnet-zero
Example:
Device(config)# ip subnet-zero
end
Example:
Device(config)# end
show running-config
Example:
Device# show running-config
copy running-config startup-config
Example:
Device# copy running-config
startup-config
Configuring IP Unicast Routing
Purpose
Enables privileged EXEC mode. Enter your
password if prompted.
Enters the global configuration mode.
Enables the use of subnet zero for interface
addresses and routing updates.
Returns to privileged EXEC mode.
Verifies your entries.
(Optional) Saves your entries in the
configuration file.