In the record of the device there is undo debugging all without log username and address. There is record even if there is no user login. Why?
In order to prevent users from forgotting to close debug after exiting, the system auto executes the command and close all debug.
1. The last login user of the system exits, the system auto creates the command. If there are other users logining on the system when exiting, the record will not be created.
2. For telnet log on the interface, it occupies vty process. If there is no person logining, the record of undo debugging all is created when telnet login is timeout or the password is false.