交换机是网络常用设备之一，也是网络必备设备之一，作为网络的基础构件，它的安全性着实成为许多工程师及网管人员的首要关注点。

https://www.docin.com/p-830687209.html

https://blog.csdn.net/netsec51sec/article/details/98956759

When working on IOS update for one standalone Cisco 3560x to meet our environment requirement, I was so surprising the total time for Cisco 3560x taking new IOS image, which was more than 30+ minutes. I was thinking to reset it during the process because it is way longer than other Cisco routers, switches and firewalls I updated before. Usually total IOS update takes less than 5 minutes from the beginning process of uploading ios to new ios fully loaded.

https://www.bilibili.com/video/BV1Ct411h7Bz?p=42&vd_source=be6abb96b4dce3b00ffc7b64f50a95a8

https://www.docin.com/p-1185877656.html

Cisco交换机IOS升级

思科官网下载IOS版本，存放地址要与Cisco TFTP Server指定的根目录地址相同。

两种方法：

1、通过Cisco TFTP上传或下载IOS (TFTP方式传输是在能够进入交换机的前提下进行的)

2、若进不了交换机，则需要Xmodem传输（使用CRT上的Xmodem功能）

1、通过TFTP传输

h3c和华为是用默认路由，ip route 0.0.0.0 0.0.0.0 x.x.x.x