为什么我会收到此 tn.write("ip address 1.1.1.1 255.255.255.255") 行的“检测到无效输入”？

Question

所以这个脚本的目的是远程登录到路由器并更改给定接口上的 IP 地址。 但是，我的脚本遇到了错误，我不知道为什么。出错的行是第 44 行。

这是我的Python脚本：

import os
import sys
import telnetlib

if (len(sys.argv) != 3):
        print "syntax: python hw06.py <device> <newip>"
        sys.exit()

router = sys.argv[1]
newip  = sys.argv[2]

interface = "Serial0/0"   # must hard code the interface to avoid disaster
TIMEOUT = 3
password1 = "user"
password2 = "cisco"
cmd = "ip address 111.11.111.11 255.255.255.0"

# 1. create a telnet object
tn = telnetlib.Telnet(router, timeout=TIMEOUT)
# 2. login/telnet to the router
tn.read_until("Password: ", TIMEOUT)
tn.write(password1 + "\n")
# 3. enter into the privilege mode
tn.write("enable\n")
tn.read_until("Password:")
tn.write(password2 + "\n")
# 4. enter into the configuration mode
tn.write("configure terminal\n")
tn.read_until("(config)#", TIMEOUT)
# 5. enter into the interface configuration mode
tn.write("int" + interface + "\n")
tn.read_until("(config-if)#", TIMEOUT)
# 6. set the new IP address
tn.write(cmd + "\r\n")
# 7. exit
#    exit from the interface configruaiton mode
tn.write("exit\n")
#    exit from the configuraiotn mode
tn.write("exit\n")
#    exit from the privilege mode
tn.write("exit\n")

print tn.read_all()  # this line is required, but not sure why?
tn.close()

oid = ".1.3.6.1.2.1.4.20.1.1"
snmp = "snmpwalk -v2c -c public %s %s" % (router, oid)

# Verify the output via SNMP
fp = os.popen( snmp )
snmp = fp.read().splitlines()   # split the outout into a list of "lines"
flag = 0
for line in snmp:
        inline = line.rstrip('\n')
        list = inline.split()
        ip = list[3]    # IP address is the 4th item on the list
        if ip == newip:
                print "The new IP address (%s) is successfully configured on Serial0/0 of %s" % (ip, router)
                flag = 1
                break
if flag == 0:
        print "failed operation: %s is not configured on Serial0/0 of %s" % (newip, router)

现在，当我运行脚本时，我输入“python script.py deviceIPaddress newInterfaceIPaddress”，这就是我得到的：

ip address 111.11.111.11 255.255.255.0
                          ^
% Invalid input detected at '^' marker.

Router4(config)#exit
Router4#exit

failed operation: 111.11.111.11 is not configured on Serial0/0 of <device>

知道为什么我会收到无效输入错误吗？ 提前谢谢您！

Answer 1

需要注意的几句话...

1. 始终使用用户名和密码配置您的 Cisco 设备
2. 请勿使用

   telnet

   ，因为通过 telnet 发送密码是不安全的。
3. 只要有可能，请使用专门用于您要完成的任务的库。 在这种情况下，

   netmiko

   非常有用。

虽然看起来您已经找到了具体问题，但使用

netmiko

...

更容易做到这一点

from netmiko import ConnectHandler

router = sys.argv[1]
newip  = sys.argv[2]

interface = "Serial0/0"   # must hard code the interface to avoid disaster
password1 = "user"        # I'm keeping this insecure value here for example
password2 = "cisco"       # I'm keeping this insecure value here for example
cmd = "ip address 111.11.111.11 255.255.255.0"


cisco_01 = {
    "device_type": "cisco_ios",
    "host": router,
    "username": "admin",
    "password": password1,
    "secret": password2         # Enable password
}

connection = ConnectHandler(**cisco_01)
prompt = connection.find_prompt()

if '>' in prompt:
    connection.enable()    # Enable mode only 'if' '>' is present in the prompt

connection.config_mode()  # Global config mode

connection.send_command(f'interface {interface}')
connection.send_command(cmd)
connection.send_command('end')

print('Closing Connection')
connection.disconnect()

如你所见，这是：

• 比telnet安全得多
• 比

  telnetlib

  容易得多，需要大量的战术工作，例如手动提示处理才能完成此任务。