IP Forwarding With Cisco Routers
Lab Exercises
Host-based Internetworking, Tuesday, 15 June ´99
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Cisco File System
Boot - startup the router
IOS - Internetworking Operating System
– keep it in Flash or boot from TFTP Server
Configuration files
– running config - in Memory
– each configuration line is active immediately
– start-up config
Command
– show startup-config
– show running-config
– show version
Host-based Internetworking, Tuesday, 15 June ´99
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initial configuration
Setup dialog
If a new router, setup is running automatically
cisco_prompt# setup
Setup will create a new start-up config
ip routing yes; but “no” to all routing protocols (especially
RIP!)
Host-based Internetworking, Tuesday, 15 June ´99
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Exercise 1
Login into the router
Connect console cable to the Serial Port
Serial connection PC to cisco router console port
– Console
% minicom [-s] [/dev/ttyS0]
or
% cu -l /dev/ttyS0 -s 9600
power on router, watch the loading messages
Login
– Console or Telnet from UNIX
Password: cisco
name> enable
Password: cisco
– Leave the session: exit
Host-based Internetworking, Tuesday, 15 June ´99
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Configure Interface
Configure Ethernet interface with setup
– IP address
– Netmask (0 - 0, 1 - 128, 6 - 254)
– “ip routing” yes; but “no” to all routing protocols
– Setup command (interactive)
– #configure terminal
– cisco(config)#interface eth o
– cisco(config)#ip address n.n.n.n mask m.m.m.m
configure e0 for row ethernet with Next IP address
example:
Network
IP address
130.65.241.16/29
130.65.241.19
Host-based Internetworking, Tuesday, 15 June ´99
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Exercise 2
configure ethernet interface
Configure Ethernet Interface
router>enable
router#conf t
router(config)#int eth 0
router(config-if)#ip addr 130.65.241.xx 255.255.255.xx
router(config-if)#no shut
router(config-if)#^z
router#sho int eth 0
Check:
– telnet to the router from one of the 1E PCs in the
row.
Host-based Internetworking, Tuesday, 15 June ´99
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Exercise 3
Check the Status
Check
– ping n.n.n.n
– traceroute n.n.n.n
Show
– Interface:
# show interface [eth/serial] 0
– ARP
# sho arp
– Configuration
write terminal
show conf (running config)or show running-config
show startup-config (boot configuration)
– Save configuration
# write [mem]
Host-based Internetworking, Tuesday, 15 June ´99
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Exercise 4 (1/2)
configure static routes
configure the router with static routes
to create static routes, use the “ip route” command:
ip route n.n.n.n m.m.m.m nexthop (g.g.g.g or device)
e.g.:
router#conf t
router(config)#ip route 130.65.241.0 255.255.255.240
130.65.241.129
Host-based Internetworking, Tuesday, 15 June ´99
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Exercise 4 (2/2)
configure static routes
now add a static default route
the default route is represented by net prefix 0.0.0.0 and
netmask 0.0.0.0, e.g.
ip route 0.0.0.0 0.0.0.0 130.65.241.142
use ping and traceroute to test
router# ping target-ip-addr
router# trace target-ip-addr
Host-based Internetworking, Tuesday, 15 June ´99
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Exercise 5 (1/2)
configure passwords
there are (at least) 6 passwords to be set: console login
password, 4 vty passwords, and the enable password
set the console password
router(config)#line con 0
router(config-line)#password mysecret
set the vty passwords
router(config-line)#line vty 0 4
router(config-line)#password mysecret
router(config-line)#exit
set the enable password
router(config)#enable password mysecret
router(config)#^Z
Host-based Internetworking, Tuesday, 15 June ´99
INET ‘99 Network Training Workshop 10/11
Exercise 5 (2/2)
configure passwords
examine the config, note that the passwords are in plaintext
# show conf
...
enable password mysecret
...
line con 0
password mysecret
...
line vty 0 4
password mysecret
login
encrypt the passwords, then examine the config again
router(config)#service password-encryption
router(config)#^Z
router#sho conf
Host-based Internetworking, Tuesday, 15 June ´99
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