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Chapter 4
Introduction to the Cisco IOS
To find a neighbor's Network layer address, you either need to go to the
router or switch itself, or you can type show cdp entry * protocol to get
the Network layer addresses you need for pinging. (Cisco Discovery Protocol
[CDP] is covered in Chapter 7.)
Traceroute uses ICMP timeouts to track the path a packet takes through
an internetwork, in contrast to Ping that just finds the host and responds.
Traceroute can also be used with multiple protocols.
Router#traceroute ?
WORD Trace route to destination address or hostname
appletalk AppleTalk Trace
clns ISO CLNS Trace
ip IP Trace
oldvines Vines Trace (Cisco)
vines Vines Trace (Banyan)
<cr>
Telnet is the best tool, since it uses IP at the Network layer and TCP at the
Transport layer to create a session with a remote host. If you can telnet into
a device, your IP connectivity just has to be good. You can only telnet to IP
addresses, and you can use Windows hosts or router prompts to telnet to a
remote device.
Router#telnet ?
WORD IP address or hostname of a remote system
<cr>
From the router prompt, you just type a hostname or IP address and it will
assume you want to telnet--you don't need to type the actual command,
telnet
.
Verifying with the Show Interface Command
Another way to verify your configuration is by typing show interface
commands, the first of which is show interface ?. That will reveal all the
available interfaces to configure. The only interfaces that aren't logical are
Ethernet and Serial.
Router#sh int ?
Ethernet IEEE 802.3
Null Null interface
Serial Serial
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