A Wireshark lab that reads real packets off a MacBook's Wi-Fi, from the Ethernet header to the round-trip time. Then two Cisco Packet Tracer builds: a subnetted two-LAN network joined by one router, and a web server reached from a client's browser.
ping -c 4pingThe coursework looks at one network from two sides. First by watching it: a Wireshark capture on macOS, read through six display filters. A single ping produced ten ICMP packets, and the first echo request was framed for the router's MAC, not Google's.
Then by building one. In Packet Tracer,
199.19.30.0/24 was split into four /26 subnets,
and a Cisco 2901 router joined two of them. The first ping failed with
100% loss because the two switch uplinks were on swapped
router ports. After re-cabling, replies came back with
TTL=127: one hop.
Each has its own pages, screenshots and presentation.
Live capture on a MacBook Air's en0, six display filters, then one ping traced from the Ethernet header to its RTT.
A Cisco 2901 and two 2960 switches in Packet Tracer. 199.19.30.0/24 subnetted to /26, a web page served across the router.
Group project. A Packet Tracer server with HTTP and HTTPS on and a page for the group, opened from a client's browser by IP.
The Project 1 network, simulated. Pick a source and a destination, and choose whether the switch uplinks are cabled to the right router ports. Watch which pings survive and what TTL comes back.
These are the real frames from wireshark_ping.pcapng. Apply
the same filters used in the lab and watch the count change: 10 in
total, 6 from the Mac, 4 from Google. The two red rows are not part of
the ping. They are port unreachable messages the Mac sent for UDP that
arrived on closed ports.
Wireshark stamps a packet when it passes the network interface.
ping reads the clock inside the program, so it also counts
the kernel, socket buffers and the time it takes to be scheduled. That
overhead was about 43 ms on the first echo and only
1 to 2 ms on the other three.
no shutdown.ifconfig en0 for ipconfig, ping -c 4 for ping -4, and the real hardware MAC.
OpenThe six filters, the HTTPS-only PSU site, and two correct DNS answers.
OpenTen ICMP frames, frame 228's headers, hop-by-hop MAC and the RTT.
OpenEight devices, the cabling, and which router port faces which LAN.
OpenBorrow 2 bits: /24 to four /26, 62 hosts each, block size 64.
Openhostname, ip address and no shutdown on R1, then show ip interface brief.
OpenStatic addresses, gateways and the custom web page on Server 1.
OpenThe 100% loss incident, the fix, and the TTL=127 replies.
OpenEach project has an animated deck. Use the arrow keys, click or swipe to move through it.