This concept explains the purpose, configuration requirements, and known limitations of login banners in controller systems.
A login banner is a user authentication feature that
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displays a customizable warning or informational message when you attempt to access the controller
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uses a delimiting character to mark the start and end of the banner text, and
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helps communicate security policies or legal notices to users before granting access.
Additional reference information
To configure a login banner, you must specify a delimiting character that signals the system to treat the enclosed text as the banner message. After entering the delimiting character, enter the message text, and then repeat the same character at the end.
The delimiter can be any single character from the extended ASCII set, but that character cannot appear inside the banner message once selected as the delimiter.
For example, to create a login banner with the delimiter #, enter:
banner login #Unauthorized access is prohibited#
When HTTP authentication is configured using TACACS+ or RADIUS, the banner message does not display on the Web UI. (Addressed CSCvr26813: C9800 - Banner not seen on GUI with TACACS authentication.)