GNS3 Overview
GNS3 is a with a graphical interface can run multiple platforms (including Windows, Linux, and MacOS, etc.) network virtualization software. Cisco network device administrator or want can be done by the relevant experiments to simulate the actions stakeholders CCNA, CCNP, CCIE and other Cisco certification exam through it. It also can be used for virtual experience Cisco IOS IOS or test to be deployed configuration implemented on a real router.
First, install experimental environment
Software installation process in detail:
https://blog.51cto.com/14307755/2426131
-------------- ------------- installation environment
1, first install the image file, click Edit, click Preferences ....
2. Click on IOS routers under Dynamips directory, click New at the bottom.
3. Select the image file storage directory.
4, choose 3725 the image file.
5, then select the image file will pop up a window to inform whether the image file upload and unzip, select YES.
6. Click Next, ( remember the installation directory must not have Chinese ).
7, where you can change the name and the module, not the default remain unchanged and click Next.
8, memory 128M has been selected to meet the conditions of use.
9, the module has a default in "GT96100-PE" board, also add the following.
10, Wic default mode remains unchanged.
11、第一次使用GNS3时一定要计算填写Idle-pc值要不然电脑CPU占用率会是100%，等后续安装完计算之后再填写。
12、镜像文件添加完成。
-------------开始实验-------------
1、点击左边的路由器图标，把新添加的路由器直接拖动到拓扑操作区。
2、启动路由器有2种方法。第一种是右击里面点击Start，第二种工具栏里点击启动按钮(也可用于多台同时启动)
3、这时再拖入一个路由器用网线连接起来，右击点击网络接口和另外一个路由器连接。
4、如果想要显示接口名称，点击工具栏的图标。
5、右击可以修改名称和模式图标。
6、点击启动按钮，启动两台路由器，这时CPU占用率会变高，对Idle值的计算来进行优化(Idle值必须运行之后才可以计算)，右击选择Idle-pc，进行计算。
7、计算之后星号为最佳推荐(实际根据CPU占用率来选择)。
8、双击打开运行的路由器，进去到运行界面，后续得操作会在这里进行。
9、除此之外，之前安装的Wireshark进行数据抓包。
(1)、右击网线，点击Start capture。
(2)、点击可以选择抓取目标，这里选择RI为例。
(3)、通讯数据就会显示在这里。
10, then we performed two routers IP configuration
(1) arranged R1IP R2 is configured to 192.168.100.50 192.168.100.30
(2) Double-click on the router, enter "configure terminal" enter the global mode.
(3) Input "interface fastEnternet 0/0"
(. 4) input address IP
(. 5) Enter the configured IP address 192.168.100.50 enter the subnet mask 255.255.255.0
(. 6) Enter no shutdown open interfaces
R2 and RI are the same configuration
11, input do show ip int b View IP address
12, will be verified whether the router communication, double R1 into the input end into privileged mode, input 192.168.100.30, four appear! and a"."! Representative ON, "." Represents an ON can also be used to obtain capture data transmission.
13, can also be used to operate the CRT.
Open CRT choose Telent.
14, open GNS3 click Edit, click on preferences, go after clicking Consle applications drop-down selection terminal CRT, click the Set update Road King, click OK, back to open the way is opened with CRT.
15, double-click the RI will see the following window.
