import getpass
import telnetlib

HOST = "192.168.1.1"
user = "1234"
password = "1234"

tn = telnetlib.Telnet(HOST,"21")

tn.read_until(b"login: ")
tn.write(user.encode('ascii') + b"r")
if password:
   tn.read_until(b"Password: ")
   tn.write(password.encode('ascii') + b"r")

tn.write(b"rebootr")
tn.write(b"exitr")

print(tn.read_all().decode('ascii'))