Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.
A container port published on a server's internal IP is still reachable from the external network. Learn how to restrict access with firewall rules without disrupting legitimate connections.
The management VPN is down, but you urgently need SSH access to a datacenter server that is still reachable through its application network. Find an alternative path to SSH using a routing trick and Linux's weak end host behavior.
On a dual-homed Linux server, a service bound to one network's IP address may still be reachable from another network. Learn how to prevent this unexpected access without disrupting legitimate connections.
On a dual-homed Linux server, a service bound to the IP address of one interface may still accept connections that arrive through the other interface. Learn how to reach such a service through an interface it doesn't listen on, using a routing trick.
Practice reading the network configuration of Linux hosts: find interface names, IP and MAC addresses, the default gateway, and detect which routes a server uses to reach different destinations.
Create an Ingress resource for a shop application with path-based routing to multiple backend services and configure /etc/hosts for local DNS resolution.
Configure a Linux NAT gateway to give Internet access to private RFC 1918 networks while keeping them hidden from the outside world.
Hone your Linux networking skills by setting up routing that lets two isolated private networks communicate.
