Cisco CCNA 2 Instructor Manual page 46

4.2 Getting Information about Remote Devices
Essential Labs:
Optional Labs:
Core TIs:
Optional TIs:
Course-Level Claim: Students can perform simple LAN troubleshooting.
Certification-Level Claim: Students can troubleshoot a device that is part of a working network.
Hands-on skills: none
4.2.1 Telnet
Telnet provides network administrators with remote connection capability. It is a part of the
TCP/IP protocol suite that operates at the application layer of the OSI model and the
application layer of the TCP/IP model. The Telnet service in Cisco devices operates as a
virtual terminal utility. Administrators can use Telnet to issue IOS commands when they are
not directly connected to the device. Telnet consumes a vty session on the router when it is
used. Remind students that vty lines 0 through 4 can be configured in a router configuration.
Since Telnet is a vty connection, a router will support simultaneous Telnet connections.
Telnet also provides a tool for troubleshooting. The establishment of a Telnet connection
confirms the connectivity and functionality of the application layer. The ping command only
confirms Layer 3 connectivity.
4.2.2 Establishing and verifying a Telnet connection
From the router console, Telnet can be used to connect to remote devices. The administrator
must type in the name of a router or the IP address of an interface to establish a Telnet
connection. The following commands can be used:
Router>131.108.100.152
Router>paris
Router>connect paris
Router>telnet paris
The figure includes an explanation of Telnet. The example shows how to console into a
directly connected router and then establish a Telnet connection with other network devices.
Telnet may also be used to connect a PC to the router, or other network device, through a
network connection instead of using a direct console cable for the connection.
Students may not understand that Telnet is widely implemented. It is not used only within a
network device to connect to other network devices. For example, Telnet can be used from the
command prompt in Microsoft Windows. It can be used to connect to other PCs, servers, or
devices.
Demonstrate various telnet connection commands.
45 - 238 CCNA 2: Routers and Routing Basics v3.1 Instructor Guide – Module 4
4.2.2, 4.2.3, 4.2.4, 4.2.5a, 4.2.5b, and 4.2.6
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Copyright © 2004, Cisco Systems, Inc.