Network security is paramount in today’s interconnected world, and protecting access to Cisco devices is a critical aspect of maintaining a secure network infrastructure. In this blog post, we will walk through the process of configuring users and passwords on a Cisco device, as well as securing access to VTY lines by requiring both a username and password. Additionally, we will implement SSH as the transport protocol for secure remote access.
Configuring Local User Authentication
Step 1: Access Privileged EXEC Mode
To begin, access the device’s Command Line Interface (CLI) and enter Privileged EXEC mode:
enableStep 2: Create Local User Accounts
Create individual user accounts with their corresponding passwords using the following command:
username <username> privilege <privilege level> secret <password>Example:
username admin privilege 15 secret MySecurePassword123Note: The privilege level can range from 0 (lowest) to 15 (highest), with 15 providing full administrative access.
Configure VTY Line Access and SSH
Step 1: Access Global Configuration Mode
Enter Global Configuration Mode with the following command:
configure terminalStep 2: Enter Line Configuration Mode
Enter Line Configuration Mode for VTY lines using the following command:
line vty 0 15Step 3: Require Login for VTY Access
To enforce username and password authentication for VTY line access, use the following command:
login localStep 4: Set Transport Input to SSH
Restrict remote access to SSH only by configuring the transport input for VTY lines:
transport input sshStep 5: Configure Login Authentication (Optional)
If not already done in the user authentication step, configure login authentication for VTY lines:
login authentication <authentication method>Example:
login authentication defaultStep 6: Set Timeout Value (Optional)
Optionally, set the timeout value for idle VTY lines to automatically disconnect inactive sessions:
exec-timeout <minutes> [seconds]Example:
exec-timeout 5 0Step 7: Exit Configuration Mode
Exit Global Configuration Mode by typing:
exitStep 8: Save Configuration Changes
Save the configuration changes to the startup configuration file:
write memoryVerifying Configuration
To ensure that the configurations have been applied successfully, log out from the device and attempt to log back in using SSH. You should be prompted to enter a username and password before gaining access to the device.
Configuring user authentication and securing VTY line access on Cisco devices are fundamental steps in enhancing network security. By requiring usernames and passwords for access and implementing SSH as the transport protocol, network administrators can ensure that only authorized users can access and manage critical network infrastructure. Regularly reviewing and updating these security measures will help maintain a strong security posture and protect the network from potential threats.
