S1. Networking and name resolution

Outcome: you can design and troubleshoot addressing, DNS and DHCP on both platforms.

Skills: IPv4 subnetting, routing, NAT, DNS zones and records, DHCP scopes and relay, hybrid name resolution concepts, firewall basics.

Labs

1. Configure the Linux router VM to route between the corp and branch networks with NAT to the internet.
2. Install DNS and DHCP on SRV1. Create forward and reverse zones. Add a DHCP scope with reservations.
3. Configure DHCP relay across the router to serve the branch network.
4. Set up a conditional forwarder and test it with nslookup and Resolve-DnsName.
5. Linux lane: configure static addressing with NetworkManager or netplan, run bind9 or dnsmasq as a second resolver, capture traffic with tcpdump.

Prove it: a network diagram, and a one-page runbook showing how you diagnosed three deliberately broken settings (wrong gateway, wrong DNS, missing route).

Certs: AZ-802 (on-premises and hybrid networking), AZ-104 (virtual networking concepts), LPIC-1 (networking fundamentals), LPIC-2 (networking configuration).