Switch and hub

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Compare traffic on switch and hub ports.

Sign in and launch

First: Static IP Addressing in a Single Subnet

Network

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PC1 and PC4 connect to SW1; PC2 and PC3 connect to HUB1; SW1 and HUB1 are linked.
PC3 observes the hub; PC4 observes the switch.
Open a console

1. Prepare the switch

PC1

ping -n -c 3 -W 1 10.0.0.3

SW1 learns PC2’s MAC address.

2. Capture traffic

PC3 and PC4

timeout 120 tcpdump -U --immediate-mode -i eth0 -w /tmp/lab-switch-hub.pcap "arp or icmp" &
capture_pid=$!
sleep 1

PC1

ping -n -c 1 -W 1 10.0.0.250
ping -n -c 3 -W 1 10.0.0.3

Address .250 is unused: the first probe will receive no reply.

3. Compare captures

PC3 and PC4

sleep 2
kill -INT "$capture_pid"
wait "$capture_pid" || true
tcpdump -nn -e -r /tmp/lab-switch-hub.pcap

Find the ARP request for .250 on both PCs. ICMP between .1 and .3 should appear on PC3, but not PC4.

Validation

Click "Check". Once all steps pass, click "End".