Configuring VPN Site-to-Site IPsec, Packet Tracer v. 7.2

Introduction

This tutorial provides a step-by-step guide to configure a Site-to-Site IPsec VPN using Packet Tracer version 7.2. A Site-to-Site VPN allows secure communication between two networks over the internet, which is essential for businesses with multiple locations. This setup will enhance your networking skills and is highly relevant for anyone pursuing a career in network administration or security.

Step 1: Set Up the Network Environment

To start, you need to create the network topology in Packet Tracer.

• Add Routers: Place two routers in the workspace to represent the two sites.
• Add PCs: Connect a PC to each router to simulate the end devices.
• Connect the Routers: Use serial connections to establish a link between the routers.

Tip: Ensure the routers are powered on and properly connected to avoid connectivity issues.

Step 2: Configure Basic Router Settings

Next, configure the basic settings on both routers.

1. Access Router CLI:

   • Click on each router and go to the CLI (Command Line Interface).

2. Configure Hostnames:

   • For Router 1:

     Router>enable
     Router#configure terminal
     Router(config)#hostname Site1
     

   • For Router 2:

     Router>enable
     Router#configure terminal
     Router(config)#hostname Site2
     

3. Set Interfaces:

   • Assign IP addresses to the interfaces facing the PCs:
     • Site1:

       Site1(config)#interface g0/0
       Site1(config-if)#ip address 192.168.1.1 255.255.255.0
       Site1(config-if)#no shutdown
       

     • Site2:

       Site2(config)#interface g0/0
       Site2(config-if)#ip address 192.168.2.1 255.255.255.0
       Site2(config-if)#no shutdown
       

Tip: Remember to configure the serial interfaces with appropriate IP addresses for connection.

Step 3: Configure Static Routing

Set up static routes on both routers to direct traffic through the VPN.

• On Site1:

  Site1(config)#ip route 192.168.2.0 255.255.255.0 [Serial IP of Site2]
  

• On Site2:

  Site2(config)#ip route 192.168.1.0 255.255.255.0 [Serial IP of Site1]
  

Common Pitfall: Ensure that the routes are pointing to the correct serial interface IPs.

Step 4: Configure IPsec VPN

This step involves the configuration of the IPsec VPN parameters.

1. Create ISAKMP Policy on Both Routers:

   Site1(config)#crypto isakmp policy 10
   Site1(config-isakmp)#authentication pre-share
   Site1(config-isakmp)#encryption aes
   Site1(config-isakmp)#hash sha
   Site1(config-isakmp)#group 2
   Site1(config-isakmp)#exit
   

2. Set Pre-Shared Key:

   Site1(config)#crypto isakmp key YourSecretKey address [Public IP of Site2]
   

3. Configure IPsec Transform Set:

   Site1(config)#crypto ipsec transform-set MYSET esp-aes esp-sha-hmac
   

4. Create a Crypto Map:

   Site1(config)#crypto map VPN-MAP 10 ipsec-isakmp
   Site1(config-crypto-map)#set peer [Public IP of Site2]
   Site1(config-crypto-map)#set transform-set MYSET
   Site1(config-crypto-map)#match address 100
   Site1(config-crypto-map)#exit
   

5. Apply the Crypto Map to the Interface:

   Site1(config)#interface s0/0
   Site1(config-if)#crypto map VPN-MAP
   

Tip: Replace placeholder values with your actual IP addresses and keys.

Step 5: Verify the Configuration

After configuration, it's important to verify that the VPN is working correctly.

• Check VPN Status:

  Site1#show crypto isakmp sa
  Site1#show crypto ipsec sa
  

• Test Connectivity:

  • Ping from one PC to the other to ensure the VPN is functioning.

Common Pitfall: Ensure that any firewalls or security settings on the hosts allow ICMP packets for ping tests.

Conclusion

You have successfully configured a Site-to-Site IPsec VPN using Packet Tracer. Key points to remember include establishing proper static routes, ensuring correct IPsec settings, and testing connectivity.

Next steps could include exploring dynamic routing protocols or experimenting with different encryption methods to enhance your VPN setup.