In today's interconnected world, it's common for enterprise networks and data centers to have multiple internet connections to enhance reliability and throughput. In such a scenario, setting up an advanced routing scheme that allows for more efficient management and utilization of available internet links can be beneficial. One method to achieve this is by using Policy-based Routing (PBR) on the CentOS 7 operating system. PBR enables defining rules for selecting the path for network traffic based on criteria other than just the destination IP address. In this article, we will discuss how to set up an advanced routing scheme using PBR for managing multiple internet connections on CentOS 7.
Prerequisites
Before you begin, make sure you have:
- A system running the CentOS 7 operating system.
- At least two active internet connections.
- Superuser privileges or sudo access to execute commands.
Step 1: Installing and Configuring Required Packages
To use PBR on CentOS 7, you first need to install the iproute2 package, which provides tools for managing routing tables and policies.
sudo yum install iproute
Step 2: Identifying Network Interfaces
Identify the names of network interfaces connected to different internet links using the ip link or nmcli d command.
Step 3: Configuring Multiple Routing Tables
For each internet connection, create a separate routing table. Modify the /etc/iproute2/rt_tables file and add entries for new tables:
100 isp1
101 isp2
Step 4: Setting Routing Rules
Set rules for routing for each routing table. Examples below demonstrate how to add rules for both internet connections:
sudo ip rule add from <local_IP_address_for_isp1> table isp1
sudo ip route add default via <gateway_isp1> table isp1
sudo ip rule add from <local_IP_address_for_isp2> table isp2
sudo ip route add default via <gateway_isp2> table isp2
Step 5: Applying PBR for Traffic Management
Now that you have configured routing tables and rules, you can define policies for traffic management based on various criteria, such as source IP addresses, ports, or protocols. The example below shows how to route all traffic from a specific IP address range through isp2:
sudo ip rule add from <IP_address_range> table isp2
Setting up an advanced routing scheme using Policy-based Routing on CentOS 7 allows for more efficient utilization of multiple internet connections. The above steps provide a basic overview of how to configure such a setup, but PBR offers many additional options and criteria for managing network traffic. It is recommended to further explore the documentation for iproute2 and experiment with different settings to ensure your network infrastructure optimally utilizes available internet links.
