Telnet multiple hosts with telnetlib3

Why did I create this script?

When you set up the new environment, you need to check whether all hosts and ports are reachable or not but you don’t want to execute telnet host port multiple times. It is a boring step that sometimes you may make a mistake here so I need to create a script to telnet multiple hosts with telnetlib3 library.

(telnetlib will be deprecated in the new version)

Requirements

Python > 3.7

Setup

Step 1: Install telnetlib3

pip install telnetlib3

Step 2: Create a main.py file

import asyncio
import telnetlib3
import io

async def telnet_welcome_message(telnet_host, telnet_port):
    telnet_connection = True
    try:
        await asyncio.wait_for(telnetlib3.open_connection(telnet_host, telnet_port), 5)
    except (asyncio.exceptions.TimeoutError, OSError) as e:
        telnet_connection = False
        print(e)
    return telnet_connection

failed_connection = []

with open("server.txt", "r") as file:
    lines = file.readlines()
    for line in lines:
        info = line.split(",")
        host = info[0]
        port = int(info[1])
        connection = asyncio.run(telnet_welcome_message(host, port))
        if not connection:
            failed_connection.append({"host": host, "port": port})

print(failed_connection)