Information
This command specifies a message to be displayed when an EXEC process is created (a line is activated, or an incoming connection is made to a vty). Follow this command with one or more blank spaces and a delimiting character of your choice. Then enter one or more lines of text, terminating the message with the second occurrence of the delimiting character.
When a user connects to a router, the message-of-the-day (MOTD) banner appears first, followed by the login banner and prompts. After the user logs in to the router, the EXEC banner or incoming banner will be displayed, depending on the type of connection. For a reverse Telnet login, the incoming banner will be displayed. For all other connections, the router will display the EXEC banner.
Rationale:
'Network banners are electronic messages that provide notice of legal rights to users of computer networks. From a legal standpoint, banners have four primary functions.
First, banners may be used to generate consent to real-time monitoring under Title III.
Second, banners may be used to generate consent to the retrieval of stored files and records pursuant to ECPA.
Third, in the case of government networks, banners may eliminate any Fourth Amendment 'reasonable expectation of privacy' that government employees or other users might otherwise retain in their use of the government's network under O'Connor v. Ortega, 480 U.S. 709 (1987).
Fourth, in the case of a non-government network, banners may establish a system administrator's 'common authority' to consent to a law enforcement search pursuant to United States v. Matlock, 415 U.S. 164 (1974).' (US Department of Justice APPENDIX A: Sample Network Banner Language)
Solution
Configure the EXEC banner presented to a user when accessing the devices enable prompt.
hostname(config)#banner exec c
Enter TEXT message. End with the character 'c'.
<banner-text>
c
Impact:
Organizations provide appropriate legal notice(s) and warning(s) to persons accessing their networks by using a 'banner-text' for the banner exec command.
Default Value:
No banner is set by default
References:
http://www.cisco.com/en/US/docs/ios-xml/ios/fundamentals/command/A_through_B.html#GUID-0DEF5B57-A7D9-4912-861F-E837C82A3881
Notes:
The default is no banner.