01Mission Tech Act 1

Networking Zero to Hero | Session 1

Browser to Wire

Put browser DevTools beside an isolated tcpdump capture and connect page-load timing to the packets that made an HTTP exchange possible.

Start the labDownload lab runnerPublic lab docs
Time45 to 60 minutes
EnvironmentWSL2 Ubuntu
StackDevTools, namespaces, HTTP, tcpdump
OutputLocal PCAP plus evidence
00

Connect three views of one request

Use browser DevTools to observe a real page load, then reproduce the request inside an isolated Linux network and prove it with a packet capture.

Browser

Method, status, timing and response headers in the Network panel.

Kernel

A connected route, bridge entries and two endpoint namespaces.

PCAP

ARP, TCP setup, HTTP request and HTTP response on the isolated wire.

PredictionBefore capturing, write down which event must happen first: ARP resolution or the TCP connection.
01

Read the browser waterfall

Open this course page in Chrome or Edge, press F12, select Network, enable Preserve log, then reload.

  1. Select the document request.
  2. Record the request method, response status and remote address.
  3. Open Timing and identify connection setup, request sent and waiting.
  4. Open Headers and identify one request header and one response header.
  5. Export a HAR if you want a browser-side artifact. The lab never uploads it.
Important distinctionDevTools explains what the browser experienced. It does not show every Ethernet frame placed on a network.
02

Prepare the isolated wire

Install the small open-source toolset and prove that WSL can create a namespace.

Ubuntu terminal
chmod +x mission-act1-labs.sh
sudo ./mission-act1-labs.sh lab01 install
sudo ./mission-act1-labs.sh lab01 doctor
Success
Every required tool and namespace creation reports PASS.
Boundary
No physical interface, host route or WSL external interface is modified.
03

Build client, bridge and server

The HTTP exchange stays between two endpoint namespaces connected by one Linux bridge.

Build and verify
sudo ./mission-act1-labs.sh lab01 build
sudo ./mission-act1-labs.sh lab01 verify
sudo ./mission-act1-labs.sh lab01 request
Kernel proofThe connected route and bridge FDB describe where Linux can send the request. HTTP 200 proves the endpoints exchanged application data.
04

Capture the request on the wire

Generate one bounded request and write the PCAP, HTTP response and packet summary to a timestamped result folder.

Capture
sudo ./mission-act1-labs.sh lab01 capture
sudo tcpdump -nn -r results/*-lab01/browser-to-wire.pcap
Packet proofFind the ARP request, ARP reply, TCP SYN, SYN-ACK, ACK, HTTP request and server response. The order is the lesson.
05

Compare DevTools with the PCAP

Build the mental mapping you will reuse for every later protocol.

DevTools statusHTTP response line
Connection timingTCP handshake packets
Remote endpointIP destination plus port

The DevTools request and isolated request are intentionally different transactions. Compare their structure, not their exact timestamps or addresses.

06

Close cleanly

Remove only Lab 01 resources. Evidence remains in the local results folder.

Cleanup
sudo ./mission-act1-labs.sh lab01 destroy