In this article, we will walk through the process of adding a route for a dual interface system running CentOS 6. Dual interface systems are common in scenarios where servers need to handle multiple networks or connect to different subnets. Properly configuring routes ensures that the server can communicate effectively across these networks.
Understanding Dual Interfaces
A dual interface means that your CentOS 6 server has two network interfaces (e.g., eth0 and eth1). Each interface can be connected to a different network. To ensure that traffic is directed correctly, you need to add specific routes that define the path for the data packets.
Prerequisites
- Access to a CentOS 6 server.
- Root or sudo privileges.
- Basic knowledge of network interfaces and routing.
Step 1: Identify Network Interfaces
First, identify the network interfaces available on your CentOS 6 system. You can use the following command:
ifconfig
This command will display all network interfaces along with their IP addresses and other relevant details.
Step 2: Check Current Routes
Before adding a new route, it is a good idea to check the current routing table. You can do this using:
route -n
This command shows you the current routes, including destination networks, gateways, and interface details.
Step 3: Add a New Route
To add a route, you will use the route command. The basic syntax for adding a route is:
route add -net [NETWORK] netmask [NETMASK] gw [GATEWAY] dev [INTERFACE]
Example
Suppose you have the following network configurations:
eth0: IP address 192.168.1.10, subnet mask 255.255.255.0eth1: IP address 10.0.0.10, subnet mask 255.255.255.0- You want to route traffic destined for the network 172.16.0.0/24 via
eth1.
The command would be:
route add -net 172.16.0.0 netmask 255.255.255.0 gw 10.0.0.1 dev eth1
Explanation of Parameters
-net 172.16.0.0: This specifies the destination network you want to reach.netmask 255.255.255.0: This defines the subnet mask for the destination network.gw 10.0.0.1: This indicates the gateway through which the traffic should flow.dev eth1: This specifies the interface to use for this route.
Step 4: Make the Route Permanent
Routes added using the route command will not persist after a reboot. To make this route permanent, you need to create or edit a configuration file for the specific network interface.
- Open the network configuration file for
eth1:
vi /etc/sysconfig/network-scripts/route-eth1
- Add the route in the following format:
172.16.0.0/24 via 10.0.0.1
- Save and exit the file.
Step 5: Restart Network Services
After configuring the route, restart the network service to apply the changes:
service network restart
Conclusion
You have now successfully added a route for a dual interface system in CentOS 6. This configuration allows your server to properly route traffic to specific networks based on your requirements. Always remember to check your routing table and test connectivity after making changes to ensure everything is functioning as expected.
