Solved: Secondary ip address

Nader ibrahimi · ‎03-03-2025

Hello to everyone

What is the exact usage of a secondary IP address in the router interface?

Any Cisco documentary is available?

M02@rt37 · ‎03-03-2025

A secondary IP address on a router interface allows the interface to belong to multiple IP subnets simultaneously. This is useful for gradual IP migration, supporting multiple subnets on a single interface, or handling legacy systems without readdressing.

There is no single cisco doc dedicated exclusively to "secondary IP addresses", but different cisco documents cover it regarding the user case...

Best regards
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M02@rt37 · ‎03-03-2025

Hello @Nader ibrahimi

A secondary IP address on a router interface allows the interface to belong to multiple IP subnets simultaneously. This is useful for gradual IP migration, supporting multiple subnets on a single interface, or handling legacy systems without readdressing.

There is no single cisco doc dedicated exclusively to "secondary IP addresses", but different cisco documents cover it regarding the user case...

Best regards
.ı|ı.ı|ı. If This Helps, Please Rate .ı|ı.ı|ı.

Joseph W. Doherty · ‎03-03-2025

BTW footnote, believe secondary interface addressing is also supported on Cisco L3 switches.