Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.
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.
Ad-hoc containers are a handy way to run command-line tools without installing them on the host. Use one to access a production Redis server and turn off a feature flag. But beware of the gotcha: the production server can only be tunneled to the localhost.
The production Kubernetes cluster lives inside a private VPC, and its API server has no public endpoint. Turn an SSH connection to the bastion host into a SOCKS proxy and teach kubectl to use it, so the cluster becomes manageable from your workstation.
An inventory service lives inside a private VPC and keeps its debugging port bound to 127.0.0.1. Use SSH local port forwarding with a jump-only bastion to query the debugging port from your workstation.
The application fleet lives inside a private VPC, reachable only through a locked-down bastion that refuses to give you a shell. Find a way to jump through the bastion and place a maintenance lock on two misbehaving servers.
Harden a bastion host so only admins can get a shell on it, operators can open tunnels to arbitrary destinations, and developers can reach only the one internal service they actually need.
A remote VM serves an app on port 80 and keeps an internal debugging port bound to 127.0.0.1. Reach the debugging port from your workstation using an SSH tunnel, without exposing it on the VM's external interface.
A production search cluster lives inside a private VPC and is reachable only from within it. Use SSH local port forwarding through a public-facing bastion host to query the cluster's API from your dev machine.
A payment webhook receiver runs as a local build on your dev machine, bound to 127.0.0.1 and invisible from the Internet. Use SSH remote port forwarding to publish it on a public-facing gateway VM so a test payment provider can reach it.
A status dashboard runs on an isolated device in your home network, with no inbound route from the Internet. Use SSH remote port forwarding with your workstation as a jump host to publish it on a public-facing gateway VM.
