In order to deliver message to potential damage or intrusion, there are several types of banners.
MADRID (config) # banner?
LINE c banner-text c, where 'c' is a delimiting character
exec Set EXEC process creation banner
incoming Set incoming terminal line banner
login Set login banner
motd Set Message of the Day banner
The banner motd offers the possibility of a daily message; the login banner will be seen to establish a telnet session, the exec banner to pass the password to privileged mode.
A log message should be noted that only authorized users are trying to access. Avoid a style message “Welcome!” On the contrary make it clear that any intrusion without authorization will be penalized by the law, thus advised to go beyond is prohibited and illegal.
Setting up a banner daily, the text must be between similar characters at the start and finish:
MADRID (config) # banner motd * You try to enter a protected system *