Python telnetlib Module: Installation Guide and Advanced Function Examples

import telnetlib  # Import the telnetlib module for Telnet communications

# Establish a connection to the remote host at port 23 (default telnet port)
tn = telnetlib.Telnet("example.com", 23)

# Wait for the login prompt and send the username
tn.read_until(b"login: ")  # Read until we see the login prompt
tn.write(b"myusername\n")  # Send the username followed by a newline character

# Wait for the password prompt and send the password
tn.read_until(b"Password: ")  # Read until we see the password prompt
tn.write(b"mypassword\n")  # Send the password followed by a newline character

# Execute a command on the remote server
tn.write(b"ls\n")  # List files in the home directory
print(tn.read_all().decode('utf-8'))  # Read and print output, decoded to utf-8

tn.close()  # Close the Telnet session

import telnetlib  # Import the telnetlib module

# Connect to the Telnet server
tn = telnetlib.Telnet("example.com")

# List of commands to execute
commands = [b"show version\n", b"show ip interface brief\n"]

# Loop through commands and execute each one
for command in commands:
    tn.write(command)  # Send the command
    print(tn.read_until(b"# ").decode('utf-8'))  # Read output until the command prompt and print

tn.close()  # Always close the connection when done

import telnetlib  # Import the necessary module
import time  # Import time for delays

try:
    # Attempt to connect to the Telnet server
    tn = telnetlib.Telnet("example.com")
    tn.read_until(b"login: ")
    tn.write(b"myusername\n")
    tn.read_until(b"Password: ")
    tn.write(b"mypassword\n")

    # Example command that may fail
    tn.write(b"invalid_command\n")  # Intentionally incorrect command
    time.sleep(1)  # Sleep to allow command execution
    output = tn.read_very_eager().decode('utf-8')  # Read output as available

    if "error" in output.lower():
        print("An error occurred: ", output)  # Check for errors in the output
    else:
        print(output)  # Otherwise, print the normal output

except Exception as e:
    print(f"An error occurred: {e}")  # Handle any other exceptions

finally:
    tn.close()  # Ensure the connection is closed