Use the telnet command to remotely access other routers.
Verify that the application layer between source and destination
is working properly.
Retrieve information about remote routers using router show
commands.
Retrieve CDP information from routers not directly connected to
you.
Background:
In this lab you will work with the telnet
(remote terminal) utility to access routers remotely. You will telnet
from your “local” router into another “remote” router in order
to simulate being at the console on the remote router. This procedure
will use your router’s Telnet client software and the remote router’s
Telnet server software. You can also “telnet” from your
workstation as a client into any router connected to your network. In
addition, you can telnet into Cisco Ethernet Switches. You can not,
however, telnet from a router or a workstation into another Windows
client or server since the Windows operating system does not support
the Telnet server daemon. A daemon (pronounced demon) is a UNIX term
that refers to a program running on a server that accepts requests for
services. You can decide whether to allow others to telnet into your
router or you may require a password for incoming Telnet sessions.
Telnet connections are referred to as line VTY 0 4 in the router
configuration file. The router can support up to 5 simultaneous
incoming Telnet sessions (0 thru 4).
Telnet is a good troubleshooting tool
since it can be used to access remote routers to gather information
when there are problems or when configuration changes are necessary.
It also tests from the OSI Application layer of the source host down
through its Physical layer and then across the network and back up the
protocol stack of the destination router. This allows you to verify
the Application layer software between source and destination hosts.
You will use telnet to access a remote router and use show
cdp neighbors to gather
information from routers that are not directly connected to you.
Tools / Preparation:
Prior
to starting the lab you will need to connect a PC w/ HyperTerminal to
a router using the router’s console Interface with a roll-over
cable.Work individually
or in teams.Before
beginning this lab you may want to read the Networking Academy First Year
Companion Guide, Chapter 13.You
should also review On-line Chapter 4.Be familiar with the following commands:
telnet ?
telnet router-name or IP
show CDP neighbors
show interface
show protocols
enable
show running-config
show startup-config
Resources Required:
PC with Windows operating
system and HyperTerminal installed
Router connected to the PC with a
console roll-over cable
At least 3 routers interconnected
via Ethernet or WAN simulation cables
Task: Connect to the router and login. Enter the password cisco if prompted.
1. What prompt did the router display?
Step 2 - Enter the help facility.
Task:
Enter
telnet ?
at the
router prompt
Explanation: The router will
respond with help with the telnet command.
2. What did the router reply with?
Step 3 - Telnet from router to router.
Task: Enter
telnet
router-name
or IP address
at the router prompt to connect to a
remote router.
Explanation: The router will prompt you for User
Access Verification of the router you remotely access. Enter the
password cisco
3. What prompt did the router display?
Step 4 - Show interfaces.
Task:
Enter
show interface
at the router
prompt.
Explanation: The router will respond with
information about its interfaces.
4. List the
interfaces, their IP address and subnet mask.
Interface
IP
Address
Subnet
mask
Step 5 - Show protocol.
Task:
Enter
show protocols
at the
router prompt.
Explanation: This command shows the
global and interface-specific status of any configured layer 3 protocols.
5. Fill in
the table below with the information that was generated by the
router you are remotely accessing.
Interface
Is
there a Carrier Detect signal
Are
the keepalive messages being received?
Step 6
- Enter
privileged mode
while connected to the remote router with telnet.
Task:
a. Enter enable
at the command prompt.
b. Enter
the password of class
Explanation: You use the enable
command
to enter privileged EXEC mode
6. What prompt did the router display?
What mode are you in?
Step 7
- Show information
about the active configuration file of the remote router.
Task: Enter show running-config at
the remote router prompt.
Explanation: The remote router will
display information on how it is currently configured.
7. What file are you viewing on the remote router? Where is this file stored?
Step 8
- Show information
about the backup configuration file of the remote router.
Task: Enter show startup-config at
the router prompt.
Explanation: The remote router will
display information on the backup configuration file stored in NVRAM.
8. What file are you viewing on the remote router? Where is this file stored?
9. What information do you see concerning the line VTY
connections?
Step 9
- Display the CDP
updates received on the local router.
Task: Enter show cdp neighbors command
at the router prompt.
Explanation: The router will respond with
information about its neighbors that have CDP enabled.
10. List all device IDs that are connected to the remote router with
which you have a telnet session.