How do I Configure a Firewall on Cisco 2821?

The Cisco 2821 router can be configured with terminal emulation software.

The Cisco 2821 router comes equipped with a software-based firewall. To configure the firewall on a Cisco 2821, you must be familiar with Cisco's security-based commands to restrict access across the network. Administrative privileges and terminal emulation software are necessary to complete this task.

Things You'll Need

• Terminal emulation software
• RS-232 serial cable
• Cisco router with IOS firewall

Instructions

1. Connect the router directly to the administrator workstation using an RS-232 cable.

2. Use the router's installation CD to install and open the terminal emulation software. If you prefer to use a third-party emulation software, that is acceptable.

3. Turn on the router and the initial boot sequence will begin. If the router has been previously configured, a prompt with the username will appear, otherwise, the prompt will appear as "Router>."

4. Type "enable" and press "Enter." Type in the router's password when the password prompt appears.

5. Type "conf t" and press "Enter." This will put the router into global configuration mode. The prompt will change to "Router (config) #."

6. Type "ip inspect?" and press "Enter." If the router is configured with the Cisco IOS software, a list of commands will appear that are specifically designed for configuring your router. If the computer displays "% Unrecognized Command," then you will need to download and install the Cisco IOS software (see Resources).

7. Use the list of available commands to configure your router. For examples of router configurations, navigate your browser to the Cisco website (see Resources).

8. Type "CNTL/Z" and press "Enter" once the configuration process is complete. This will return the terminal emulation software back to privileged mode.

9. Type "show ip route" and press "Enter." A list of all neighboring IP addresses will be displayed, indicating that the configuration is complete and the router is communicating with known workstations.

10. Type "show running-config" and press "Enter." Your new running configuration will display.

11. Type "copy running-config startup-config" and press "Enter." This will copy your current configuration to your start-up configuration and save it to the router's memory.

Tips & Warnings

• If you have never configured a router, this task can become frustrating in a hurry. If you are not sure of your ability to configure your router, it is best to contact a qualified network administrator to help you.

References

• Cisco: 2800 Series Quick Start Guide

Resources

• Cisco: Downloads
• Cisco: IOS Firewall Configuration