After a search on configuration guide and documentation, I didn't any evidence of a limitation on ip address secondaryconfiguration on a certain VLAN on 450x SUP6E.

Anyone know where I can found such information or confirm if is there any ?

By my perception, there is no limitation on secondary IP possible to configure on a SVI or interface.


1 Answer 1


There is no defined maximum limit for the amount of secondary IP addresses. However using a lot of secondary IPs usually points to a poor network design. What is your need for these secondary addresses?

Here is a quote from Ivan Pepelnjak:

… and pasted the results into the console window. No problem, a router accepted at least 250 secondary addresses. Chris repeated the process on his Catalyst switch and reported that he stopped the test after approximately 150 addresses (obviously way more than what he needed).

Ivan IOS hints maximum secondary IP

Also from Cisco's FAQ:

Q. What are the maximum number of secondary IP addesses that can be configured on a router interface?

A. There are no limits on configuring secondary IP addresses on a router interface. For more information, refer to Configuring IP Addressing.

Cisco FAQ

If you really want to find out then you could test it with a script generating configuration and then pasting it in. My guess is you will get bored before you run into any limit though.

  • I wondered whether secondaries consumed an idb, in case you'd hit that limit; I tested with 20 secondaries... apparently they don't consume an idb AFAICT Apr 2, 2014 at 8:35
  • Thanks, I will not go further that 10 secondaries so it will be fine.
    – cgasp
    Apr 2, 2014 at 9:24

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