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Docker 101: List Docker Networks and Inspect the Default Bridge
Explore the container networks of a freshly installed Docker host: find the default network, its subnet and gateway, and the Linux interface behind it.
Challenges
Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.
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Docker 101: Reach a Container Without Publishing a Port
Practice accessing a containerized service directly from the Docker host using its IP address.
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Call an HTTP API with curl: Reading Resources
Learn the basics of accessing HTTP APIs from the command line: call different endpoints, read the response body, headers, and status code, follow redirects, and request an alternative representation of a server resource.
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Identify the Source of Unexpected Requests in a Kubernetes Cluster
An internal service started receiving requests from unexpected IP addresses. Identify the unexpected sources and find out which workloads and teams are behind them.
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Identify the Source of Unexpected Requests in an On-Prem Network
An internal service started receiving requests from unexpected IP addresses. Identify the unexpected sources and find out which systems are behind them.
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Inspect Network Interfaces, IP Addresses, and Routes on a Linux Host
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.
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List All Tags in a Container Repository
Practice discovering what has been published to a remote container repository by listing its tags using crane, regctl, or a direct call to the registry HTTP API.
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Inspect a Container Image Without Pulling It
Explore the OCI image index, manifests, and configuration of a remote multi-platform image - without pulling a single byte of filesystem layers into the local Docker daemon.
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Inspect OCI Image Layout of Single- and Multi-Platform Images
Save container images as OCI layouts and explore the on-disk structure of single-platform (manifest-based) and multi-platform (index-based) images.
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Docker 101: List Containers and Identify Running, Successfully Finished, and Crashed Tasks
Practice listing containers and inspecting their state to identify running, exited, and crashed applications - a vital skill for day-to-day operation of containerized systems.