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ccna 200-301 odom pdf download.The usernamesecret command is more secure because it uses a stronger arithmetic V MD5 hash to conceal the password. MD5 is more secure than the standard type 7 algorithm used by the service password-encryption command. The protection of MD5 is useful when passwords need to travel across the network or be stored on a TFTP server. When configuring combinations of username and password, be sure to observe the password length limit.Note: IOS 15 introduces an additional option in the username secret command. The administrator can specify to use the SHA256 encryption algorithm for the password text string. Cisco recommends using SHA256 in place of the MD5 encryption algorithm. The console, VTY, and aux ports must be configured to be accessed using the username and password combinations in the local database. To do this, the login command needs to be changed to loginlocaL in each line wiring soap Note: All examples later in this chapter use the username secret command in place of username password2.1.3 Configuring Enhanced Security for Virtual Logins2.1.3.1 Enhancing the Login ProcessImplementing a password and local authentication does not prevent a device from being a target of an attack. Devices must be configured in the network to detect and prevent these attacks.2.1 Protecting Access to Devices 31The login enhancement feature of Cisco 10S provides additional security to these devices when attacks that slow the network down (such as dictionary attacks and DoS attacks) create a virtual connection to the IOS device. By enabling a detection profile, the network device can respond to multiple failed login attempts by denying further connection requests or blocking the login. This blocking can be configured for a period of time called a silent period. Also, by configuring ACLs using the address associated with the system administrator, it is possible to allow legitimate connection attempts to be released during the silent period.2.1.3.2 Configuring Login Enhancement FeaturesThe CiscoIOS login enhancement command can improve the security of virtual login connections by enabling the login process with the following specific parameters The delay between two consecutive login attempts.Disable login if a DoS attack is suspected. Generates syslog messages for login detection. These enhancements cannot be applied to console connections. In a console connection, we assume that only authorized personnel can physically