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文件名称：VTY访问举例-CCNA中文版PPT
文件大小：10.75MB
文件格式：PPT
更新时间：2021-04-25 17:53:02
CCNA
VTY访问举例
只允许网络192.89.55.0 内的主机连接路由器的 vty 通道
access-list 12 permit 192.89.55.0 0.0.0.255
line vty 0 4
access-class 12 in
Controlling Inbound Access
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Slide 1 of 1
Purpose: This example shows how to restrict incoming telnet sessions to the router’s vty ports.
Emphasize: The access-class is applied as an input filter.
Note: Ask the student the effect of changing the direction of the access-class to outbound instead of inbound.
Now the router can accept incoming telnet sessions to its vty ports from all hosts but will block outgoing telnet sessions from its vty ports to all hosts except hosts in network 192.89.55.0.
Once a user is telneted into a router’s vty port, the outbound access-class filter will prevent the user from telneting to other hosts as specified by the standard access-list.
Remember, when an access-list is applied to an interface, it only block or permit traffic going through the router, it does not block or permit traffic initiated from the router itself.