1. IP Network Layer and Ethernet Encapsulation
Lab exercises

2. IP addresses Host IP address Network address Netmask Broadcast address
_____
Network address
Netmask
Broadcast address

3. Class diagram
/25
.41
/25
eth0
eth0
.42
eth0 .2 .1
eth0
/25
/25
/25
/29
eth0
.58
.57
eth0
eth0
.49
eth0
.50
eth0
.18
.17
eth0
eth0 .9
eth0
.10
.135
eth1
/25
/25
/25
/25
eth0
.74
.73
eth0
eth0
.65
eth0
.66
eth0
.34
.33
eth0
eth0
.25
eth0
.26
/25

4. Ping - Exercise 1 Step 1 Load Ethernet Driver Check
# modprobe eepro100
Check
# lsmod
see if module loaded

5. Ping - Exercise 1 (cont.) Step 2 Configure interface Check:
# ifconfig eth0 <IP address> netmask <netmask> broadcast <broadcast>
For Linux < 2.2
route add -net <network> netmask <netmask>
Check:
# ifconfig - check interface
# netstat -nr - check route to network

6. Ping - Exercise 1 (cont.) Step 3 Step 4 Ping Try: Monitor traffic
# ping <remote IP address>
Try:
other machines
broadcast address
Step 4
Monitor traffic
# tcpdump -i eth0 -n

7. Ping - Exercise 2 Step 1 Step 2 Step 3 Find your own MAC address
# ifconfig
Step 2
Ping your neighbor
# ping <IP address>
Step 3
Show ARP cache & look for their MAC addresses
# arp -n

8. Ping - Exercise 2 (cont.) Step 4 Step 5
Show traffic including Ethernet header
# tcpdump -i eth0 -n -e
Step 5
On other window (e.g. ALT+F2)
Look for ARP frames
# arp -d <IP address> - Flash ARP entry
# ping <IP address>
Go back to the first window to look for ARP frames