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[ScreenOS] Error in Web UI/CLI: 255.x.0.0 exceeds largest network mip supports (class B)



Article ID: KB29693 KB Last Updated: 03 Dec 2014Version: 1.0

This article describes the following error message:

255.x.0.0 exceeds largest network mip supports (class B)

It is sometimes encountered in the Web UI/CLI when configuring a mapped IP (MIP) on an egress interface.


When attempting to configure a MIP on an egress interface with a subnet mask (for example,, the configuration setup fails sometimes with the following error message logged in the Web UI/CLI: exceeds largest network mip supports (class B)


The largest network supported by a MIP is Class B (


This error message is issued in accordance with the design of the firewall.

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