Intermediate · Available now
Networking & Systems Deep Dive
The network, from the cable to the packet capture.
Twelve lessons that go beyond the basics: encapsulation, routing, DNS, TLS, firewalls, wireless, subnetting and packet analysis. The knowledge that makes troubleshooting and security work precise.
What you will be able to do
- Trace a packet through every layer of the stack
- Explain routing, switching, NAT and segmentation
- Read DNS, TLS and DHCP behaviour with confidence
- Subnet a network without guessing
- Capture and interpret traffic in a legal lab
- Troubleshoot a network methodically instead of randomly
Curriculum
12 lessons · 148 minProtocols and packets
What actually happens between two machines on a network.
- 12 min
OSI, TCP/IP and encapsulation
Why the models exist, how headers stack, and what each layer can and cannot see.
- 12 min
Ethernet, switching and ARP
Frames, MAC addresses, switch forwarding and the ARP conversation that makes local delivery work.
- 13 min
IP routing, gateways and NAT
How a packet chooses a path, why a default gateway matters and what NAT rewrites.
Core services
The services almost everything else depends on.
- 13 min
DNS in depth
Records, caching, recursion and the security issues that come with being the internet's address book.
- 12 min
DHCP, IPv6 and neighbour discovery
Automatic addressing in both IP families, and why IPv6 changes the security questions.
- 13 min
TLS, certificates and PKI
What the handshake proves, what a certificate authority trusts, and where TLS stops helping.
Network defence
Controls that shape what can talk to what.
- 12 min
Firewalls, ACLs and segmentation
How rules are evaluated, why order matters and how segmentation limits lateral movement.
- 12 min
VLANs, Wi-Fi and network access control
Separating broadcast domains and deciding which devices may join the network at all.
- 13 min
Packet analysis with Wireshark
Capture traffic legally, filter it usefully and reconstruct a conversation from packets.
Operations
Make the network observable and fixable.
- 13 min
Subnetting and CIDR without panic
A repeatable method for network, broadcast and host ranges, plus the shortcuts worth memorising.
- 11 min
Structured network troubleshooting
A bottom-up and top-down method that avoids changing five things at once.
- 12 min
Flow logs, NetFlow and monitoring
What flow data can tell you that packet captures cannot, and how to spot unusual traffic.