iPerf is a commonly used command-line tool for measuring network bandwidth between two computers. It’s useful for testing the performance of your network infrastructure. Here’s a step-by-step guide on how to use iPerf to test bandwidth between two Linux servers:

1. **Install iPerf:**
Make sure iPerf is installed on both the source and destination servers. You can install it using your Linux distribution’s package manager. For example, on Debian/Ubuntu, you can use:
“`
sudo apt-get install iperf
“`

2. **Choose a Role:**
Decide which server will act as the server (receiver) and which one will act as the client (sender).

3. **Run iPerf Server:**
On the server that will act as the receiver, run the following command to start iPerf in server mode:
“`
iperf -s
“`
This will start iPerf in server mode, listening for incoming connections.

4. **Run iPerf Client:**
On the other server that will act as the sender, run the following command to initiate the bandwidth test:
“`
iperf -c <server_ip>
“`
Replace `<server_ip>` with the IP address of the server running in server mode.

By default, iPerf will run for 10 seconds using TCP. It will display the measured bandwidth at the end of the test.

5. **Customize Options (Optional):**
You can customize the behavior of iPerf by adding additional command-line options. For example, you can specify the duration of the test, use UDP instead of TCP, set the port number, etc. Run `iperf –help` to see a list of available options.

Here’s an example of a more customized command:
“`
iperf -c <server_ip> -t 30 -u -p 5001
“`
In this example, the client will run a UDP test for 30 seconds on port 5001.

Remember to adjust firewalls and network configurations if necessary to allow traffic between the two servers.

Keep in mind that iPerf measures the raw network bandwidth between the two servers. It’s important to interpret the results in the context of your network infrastructure and potential external factors that could affect the test.

Additionally, always ensure you have the necessary permissions and authorization to perform network tests between the servers.