Linux Networking Course

Lesson 1 • IP Addressing and Subnetting

Covers IPv4 and IPv6 address structures, CIDR notation, and subnet calculation. Prepares students to assign and plan address spaces on Linux hosts.

Lesson 2 • Linux Network Interface Basics

Introduces physical and virtual network interfaces in Linux and their naming conventions. Students identify and inspect interfaces using core command-line tools.

Lesson 3 • Core Networking Protocols

Examines ARP, ICMP, TCP, and UDP behavior at the packet level. Connects protocol theory to observable Linux network behavior.

Lesson 4 • Linux Kernel Network Stack Overview

Traces how the Linux kernel processes inbound and outbound packets through its network stack. Provides context for later topics on filtering and routing.

Lesson 1 • Using ip and iproute2 Tools

Teaches the iproute2 suite as the primary interface management toolkit, replacing legacy ifconfig. Students configure addresses, links, and neighbors from the command line.

Lesson 2 • NetworkManager and systemd-networkd

Compares NetworkManager and systemd-networkd as modern configuration daemons. Students write unit files and connection profiles for both systems.

Lesson 3 • Interface Bonding and Teaming

Covers link aggregation modes including active-backup, LACP, and round-robin. Students configure bonded and teamed interfaces for redundancy and throughput.

Lesson 4 • Dynamic Configuration with DHCP

Explains DHCP lease acquisition and the role of dhclient and NetworkManager. Students configure interfaces to obtain addresses dynamically and inspect lease details.

Lesson 1 • Enabling IP Forwarding

Configures the Linux kernel to forward packets between interfaces, enabling router behavior. Students set sysctl parameters and persist them across reboots.

Lesson 2 • Policy-Based Routing

Introduces multiple routing tables and ip rule to implement policy-based routing. Students route traffic from different sources through separate gateways.

Lesson 3 • Linux Routing Table Fundamentals

Explains how the kernel selects routes using the routing table and policy rules. Students read, add, and delete routes using ip route commands.

Lesson 4 • Dynamic Routing with OSPF and BGP

Introduces FRRouting to run OSPF and BGP on Linux, replacing dedicated router hardware. Students configure basic neighbor relationships and advertise prefixes.

Lesson 1 • Authoritative DNS with BIND

Configures BIND as an authoritative server for forward and reverse zones. Students write zone files with A, AAAA, MX, CNAME, and PTR records.

Lesson 2 • DNS Troubleshooting Techniques

Applies dig, drill, and tcpdump to diagnose resolution failures and misconfigurations. Students trace queries from stub resolver to authoritative server.

Lesson 3 • DNS Resolution on Linux Hosts

Explains the resolver library, /etc/resolv.conf, and nsswitch.conf lookup order. Students control how a Linux host resolves names and override defaults.

Lesson 4 • Deploying a Caching Resolver

Installs and configures Unbound as a validating, caching recursive resolver. Students tune cache size, enable DNSSEC validation, and restrict query access.

Lesson 1 • nftables Modern Ruleset Design

Introduces nftables as the successor to iptables with a unified syntax. Students write nft scripts covering filtering, NAT, and sets for efficient matching.

Lesson 2 • iptables Rule Writing

Teaches iptables syntax for filtering, NAT, and mangle operations. Students build INPUT, OUTPUT, and FORWARD chains for a typical server.

Lesson 3 • Stateful Firewall and Connection Tracking

Leverages conntrack to build stateful rules that allow established sessions. Students configure state-based policies and inspect the connection tracking table.

Lesson 4 • Netfilter Architecture and Hooks

Explains the Netfilter framework, its hook points, and how tables and chains relate. Provides the conceptual model needed to write correct firewall rules.

Lesson 1 • OpenSSH Server Hardening

Secures sshd by disabling password auth, restricting users, and tuning ciphers. Students apply CIS-aligned settings and test access controls.

Lesson 2 • SSH Tunneling and Port Forwarding

Uses SSH local, remote, and dynamic forwarding to tunnel traffic securely. Students build SOCKS proxies and expose internal services through SSH tunnels.

Lesson 3 • Time Synchronization with chrony and NTP

Configures chrony as an NTP client and server for accurate system time. Students set stratum, restrict access, and verify synchronization status.

Lesson 4 • Kea DHCP as a Modern Alternative

Introduces Kea as a high-availability DHCP server with REST API management. Students configure dual-stack pools and enable lease synchronization between peers.

Lesson 1 • Interface and Socket Statistics

Extracts interface counters, socket states, and queue depths using ss, netstat, and ethtool. Students correlate statistics with observed network problems.

Lesson 2 • SNMP and Prometheus Node Exporter

Configures SNMP agents and Prometheus Node Exporter to expose network metrics. Students scrape metrics and build Grafana dashboards for interface utilization.

Lesson 3 • Log Analysis for Network Events

Parses syslog, journald, and firewall logs to identify network anomalies. Students write journalctl queries and correlate log events with packet captures.

Lesson 4 • Network Performance Testing

Measures throughput, latency, and jitter using iperf3, ping, and hping3. Students establish baselines and identify bottlenecks in lab topologies.

Lesson 1 • Linux Bridge and VLAN Networking

Creates software bridges and 802.1Q VLAN interfaces to segment traffic on Linux. Students build multi-VLAN topologies and connect virtual machines.

Lesson 2 • WireGuard VPN Configuration

Deploys WireGuard point-to-point and hub-and-spoke VPN topologies on Linux. Students generate keys, write interface configs, and verify encrypted tunnels.

Lesson 3 • Container and Kubernetes Networking

Explains Docker bridge networking, CNI plugins, and Kubernetes pod networking models. Students trace packet paths through container network namespaces.

Lesson 4 • OpenVPN Site-to-Site and Remote Access

Configures OpenVPN with TLS certificates for site-to-site and road-warrior scenarios. Students manage a PKI, push routes, and restrict client access.