Basic Firewall Configuration in Cisco Packet Tracer
A firewall is a hardware or software network security device that monitors all incoming and outgoing traffic based on a defined set of security rules, it accepts, rejects, or drops that specific traffic.
- Accept: Allow traffic.
- Reject: Block traffic but respond with “reachable error”.
- Drop: Block unanswered traffic firewall establishes a barrier between secure internal networks and untrusted external networks, such as the Internet.
Steps to Configure and Verify Firewall in Cisco Packet Tracer:
Step 1: First, open the Cisco packet tracer desktop and select the devices given below:
IP Addressing Table:
- Then, create a network topology as shown below the image.
- Use an Automatic connecting cable to connect the devices with others.
Step 2: Configure the PCs (hosts) and server with IPv4 address and Subnet Mask according to the IP addressing table given above.
- To assign an IP address in PC0, click on PC0.
- Then, go to desktop and then IP configuration and there you will IPv4 configuration.
- Fill IPv4 address and subnet mask.
- Repeat the same procedure with the server
- Assigning an IP address using the ipconfig command, or we can also assign an IP address with the help of a command.
- Go to the command terminal of the PC.
- Then, type iPConfig <IPv4 address><subnet mask><default gateway>(if needed)
Example: ipconfig 188.8.131.52 255.0.0.0
- Repeat the same procedure with other PCs to configure them thoroughly.
Step 3: Configuring the firewall in a server and blocking packets and allowing web browser.
- Click on server0 then go to the desktop.
- Then click on firewall IPv4.
- Turn on the services.
- First, Deny the ICMP protocol and set remote IP to 0.0.0.0 and Remote wildcard mask to 255.255.255.255.
- Then, allow the IP protocol and set remote IP to 0.0.0.0 and Remote wildcard mask to 255.255.255.255.
- And add them.
Step 4: Verifying the network by pinging the IP address of any PC.
- We will use the ping command to do so.
- First, click on PC2 then Go to the command prompt.
- Then type ping <IP address of targeted node>.
- We will ping the IP address of the server0.
- As we can see in the below image we are getting no replies which means the packets are blocked.
Check the web browser by entering the IP address in the URL.
- Click on PC2 and go to desktop then web browser.
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