Python 获取套接字。错误：[Errno-2]名称或服务未知

我有一项任务是从许多Cisco设备获取信息，根据下面的脚本，我试图远程登录到路由器，但每次都会收到

socket.gaierro

error

import telnetlib
import os
cwd = os.getcwd ()  # Get the current working directory (cwd)
files = os.listdir (cwd)  # Get all the files in that directory
print ("Files in %r: %s" % (cwd, files))
with open ('/home/user1/Ahmed_Yousry/telnet_ip.txt') as f:
    Devices = f.read ().splitlines ()

username = []
password = []

for device in Devices:
    print ('connecting to  ' + HOST)
    HOST = device
    try:
        username = "xxxxx"
        password = "xxxxx"
    except:
        try:
            username = "xxxxx"
            password = "xxxxx"
        except:
            try:
                username = "xxxxx"
                password = "xxxxx"
            except:
                print ('Unable to connect!' + HOST)
            continue
    tn = telnetlib.Telnet (HOST)
    tn.read_until (b"username: ")
    tn.write (username.encode ('ascii') + b"\n")
    if password:
        tn.read_until (b"password: ")
        tn.write (password.encode ('ascii') + b"\n")
    output = tn.write (b"show run | i username\n")
    print (output)


socket.gaierror: [Errno -2] Name or service not known