How to use the command 'netselect' (with examples)

The ’netselect’ command is a tool used for speed testing network servers in order to choose the fastest one. It provides information about latency, nameserver resolution, and allows you to define the maximum time to live (TTL) for the test. By specifying the number of fastest servers to be printed, you can also get a list of the N fastest servers among a group of hosts.

Use case 1: Choose the server with the lowest latency

Code:

sudo netselect host_1 host_2

Motivation:

This use case is useful when you need to select a network server with the lowest latency for optimal performance and minimal delay in communication. By comparing the latency between different servers, you can make an informed decision about which server to use.

Explanation:

• sudo: This command is run with administrative privileges.
• netselect: The command being executed.
• host_1 host_2: The hosts you want to compare in order to choose the one with the lowest latency.

Example output:

The best server is: host_2

Use case 2: Display nameserver resolution and statistics

Code:

sudo netselect -vv host_1 host_2

Motivation:

When troubleshooting network connectivity issues, it can be helpful to display nameserver resolution and gather more detailed statistics about the network servers. This information can aid in identifying any potential bottlenecks or issues with specific servers.

Explanation:

• -vv: Enables verbose output, providing more detailed information about nameserver resolution and statistics.
• host_1 host_2: The hosts you want to analyze.

Example output:

Nameserver resolution:
   host_1: 192.168.1.100 (52ms)
   host_2: 192.168.1.200 (45ms)

Use case 3: Define maximum TTL

Code:

sudo netselect -m 10 host_1 host_2

Motivation:

The time to live (TTL) is the maximum number of network hops a packet can take before it is discarded. By defining a maximum TTL, you can limit the number of hops the speed test packet takes, providing a more accurate representation of network latency for the specific environment you are testing. This is especially useful when testing networks with long routes or complex infrastructures.

Explanation:

• -m 10: Defines the maximum TTL as 10.
• host_1 host_2: The hosts you want to test with the defined maximum TTL.

Example output:

The best server is: host_1

Use case 4: Print fastest N servers among the hosts

Code:

sudo netselect -s N host_1 host_2 host_3

Motivation:

In some scenarios, you may want to get a list of the N fastest servers among a group of hosts. This can help you identify the top-performing servers and choose the one that best fits your needs.

Explanation:

• -s N: Specifies that the output should include the fastest N servers.
• host_1 host_2 host_3: The hosts you want to compare in order to choose the fastest N servers.

Example output:

The fastest 2 servers are: host_2, host_3

Use case 5: List available options

Code:

netselect

Motivation:

When you want to explore the available options and functionalities of the ’netselect’ command, running the command without any arguments will display a list of all the available options. This allows you to better understand the capabilities of the command and use it more effectively.

Explanation:

No additional arguments are used in this use case.

Example output:

Usage: netselect [-n] [-b] [-w] [-i] [-l] [-v] [--xml] [-c arg] [-m arg] [-p arg] [-s arg] [--debug][--version] [--help] [host1 ...]"

Conclusion:

The ’netselect’ command is a versatile tool for speed testing network servers and choosing the fastest one based on various criteria. By using the different options available, such as comparing latency, displaying nameserver resolution, defining a maximum TTL, or printing the fastest N servers, you can make informed decisions about network connectivity and optimize your network performance.