| 4.2 |  | Getting Information about Remote Devices |
| 4.2.2 |  | Establishing and verifying a Telnet connection |

| The Telnet IOS EXEC command allows a user to Telnet from one Cisco device to another. With Cisco's implementation of TCP/IP, it is not necessary to enter the command connect or telnet to establish a Telnet connection. The hostname or the IP address of the remote router may be entered. To end a Telnet session, use the EXEC commands exit or logout. To initiate a Telnet session any of the following alternatives can be used: Denver>connect paris Denver>paris Denver>131.108.100.152 Denver>telnet paris A hostname table or access to DNS for Telnet must be present for a name to work. Otherwise, the IP address of the remote router must be entered. Telnet can be used to perform a test to determine whether or not a remote router can be accessed. As shown in Figure , if Telnet is used successfully to connect the York router to the Paris router, then a basic test of the network connection is successful. This operation can be performed at either the user or privileged EXEC levels. If remote access can be obtained through another router, then at least one TCP/IP application can reach the remote router. A successful Telnet connection indicates that the upper-layer application functions properly. If Telnet to one router can occur, but failure to another router occurs, it is likely that specific addressing, naming, or access permission problems caused the Telnet failure. It is possible that the problem exists on this router or on the router that failed as a Telnet target. In this case, the next step is to try ping, which is covered later in this lesson. Ping allows testing of end-to-end connections at the network layer. Once the Telnet is completed, log off the host. The Telnet connection will terminate after ten minutes of inactivity by default or when the exit command at the EXEC prompt is entered.
| Lab Activity Lab Exercise: Establishing and Verifying a Telnet Connection In this lab, the students will establish a Telnet connection to a remote router and verify that the application layer between source and destination is working properly.
| Web Links A Telnet Tutorial http://oregonstate.edu/aw/ tutorials/telnet/