Detailed step-by-step guide to checking cloud server bandwidth

Checking Cloud Server bandwidth helps administrators, DevOps, and VPS users ensure network transmission performance, detect bottlenecks, and optimize infrastructure costs. Vcloudia will provide detailed instructions on how to check using different tools in the article below.

How to check cloud server bandwidth using Iperf

iPerf3 is a popular network performance testing tool that operates on a client/server model. This tool allows you to measure the maximum achievable bandwidth between two machines by creating a back-and-forth data stream and measuring the actual transmission speed. The steps to check cloud server bandwidth using Iperf are as follows:

Step 1: Install iPerf3 on Ubuntu/Debian operating systems

On Ubuntu/Debian, iPerf3 is available in the software repository. You just need to run the command:

sudo apt update && sudo apt install iperf3 -y

Step 2: Launch iPerf3 in Server mode on the machine

iPerf3 requires at least two machines (or two terminal sessions), one acting as the Server and one as the Client.

- On the server, start iPerf in server mode using the command: iperf3 -s. After running, iPerf3 will display a message that the server is listening, ready to accept connections.

- On the client machine, perform a test to the server using the command: iperf3 -c <server_IP_address>. Replace <server_IP_address> with the IP or hostname of the machine running in the previous step. By default, this command will transmit data from the client to the server for 10 seconds to measure the upload speed (from client to server).

If you want to check the reverse direction (download speed from server to client), add the -R option on the client command:

iperf3 -c <server_IP_address> -R

The -R option will reverse the roles, requesting the server to send data to measure the download bandwidth on the client side. In both cases, after the default test duration of 10 seconds, the results will be printed to the terminal of both the client and the server.

Step 3: Advanced options

iPerf3 provides various options to customize the measurement:

-t 30: Measure for 30 seconds instead of the default 10 seconds

-P 4: Use 4 parallel TCP streams to saturate the bandwidth

-u: Switch to UDP test (must additionally specify speed with -b)

Step 4: Read the results

At the end of the measurement session, iPerf3 will print the results on both the client and server sides. The iPerf3 result consists of multiple lines, where the last line contains important parameters such as:

- The Bandwidth column indicates the actual network speed (Mbits/sec)

- Retr: The number of packet retransmissions (the lower, the better)

- Jitter and Lost/Total datagrams if testing with UDP

Measuring cloud server bandwidth using Speedtest

Speedtest CLI is the official command-line version of the Internet speed testing service Speedtest.net (Ookla). The tool is convenient for measuring Internet speed (to global Speedtest servers) right on the terminal, without needing a web browser.

The steps to check cloud server bandwidth using Speedtest are as follows:

Step 1: Install the official Speedtest CLI from Ookla

- First, you need to install iPerf3 on both servers (sending and receiving machines) using the following command:

sudo apt update && sudo apt install iperf3 -y

- After installation, on the machine acting as the server, you start iPerf3 using the command:

iperf3 -s

Step 2: Run the network speed test command

Once installed, run the speedtest-cli command without parameters so the system automatically selects the nearest Speedtest server (based on the lowest ping latency) and proceeds with the measurement. On the first run, type YES to accept the terms.

Step 3: Select a specific test server

If you want to choose a specific server to test, you can:

- Type speedtest -L to list the available servers

- Then use speedtest -s <server-id> to test with the desired server ID

Step 4: Export data as a file

To export the test data to CSV or JSON format for storage or further analysis, use the command:

--format=csv or --format=json

--share: Create a link to share the results

Step 5: Analyze the results

The output results will include:

- Ping: network latency (ms), the lower, the better

- Download/Upload: download and upload speeds (Mbps)

- Result URL: used to share with the provider if needed

How to use Nload to monitor cloud server bandwidth

Nload is a command-line tool for monitoring network bandwidth in real-time. Unlike iPerf3 or Speedtest (which perform active measurements), Nload monitors the live traffic running on the server's network interface. Measure cloud server bandwidth according to the following instructions:

Step 1: Install the tool

To use the Nload tool to monitor network bandwidth in real-time, you need to install it beforehand on the Linux operating system. The installation is quite simple and depends on each distribution:

- On Ubuntu/Debian: simply run the command:

sudo apt install nload

- On CentOS/RHEL: you need to activate the EPEL repository first, then install it using:

sudo yum install epel-release

sudo yum install nload

- On Fedora or Arch Linux: it can also be installed quickly via dnf or pacman.

Most popular Linux distributions today support the nload package in their official repositories, so you can install and use it immediately without needing to compile it manually.

Step 2: Run the tool

Type the nload command to monitor all network interfaces, or specify a particular interface, for example, nload eth0, to track only the eth0 network port. After running, the Nload interface screen will begin drawing a traffic graph and continuously updating the metrics.

Step 3: Analyze the displayed information

On the Nload screen, you will see a graph displayed:

- Top: Incoming – data receiving speed

- Bottom: Outgoing – data sending speed

The main indicators to observe:

- Curr: current speed

- Avg: average speed

- Max: maximum recorded speed

- Ttl: total traffic used during the session

Use the left/right arrow keys (or Enter) to switch between network cards if there are multiple interfaces (when running without specifications or using -m). Press q (or Ctrl+C) to exit Nload.

How to check bandwidth through the cloud provider's control panel

Most cloud service providers integrate built-in bandwidth monitoring tools in their control panels. This is a convenient way to check cloud server bandwidth for quick monitoring without the need to install anything else:

- Real-time bandwidth graphs: Many platforms like DigitalOcean, Linode, and Vultr display Inbound/Outbound bandwidth graphs in real-time (6h, 24h, 7d, 14d). Network traffic is clearly represented by colored lines, making it easy to monitor right from the dashboard.

- Detailed ingress/egress metrics: AWS (CloudWatch), Azure Monitor, and GCP provide NetworkIn/Out data over time. You can view graphs, create alerts, or retrieve data via API to track traffic into/out of the VM.

- Monthly traffic statistics: Cloud control panels display the total data used monthly, especially egress volume. DigitalOcean and several other platforms show how many GB/TB you have used and how much is left before you are charged.

Conclusion

Through the article above, you have grasped various methods to check cloud server bandwidth in different ways. Periodically checking cloud server bandwidth not only helps detect potential issues early, but also helps control costs, especially with platforms that charge based on egress data volume.