MetalLB is a Kubernetes-native load balancer for bare-metal clusters. Two cooperating workloads implement the system: a cluster-scoped controller that allocates IP addresses from CRD-defined IPAddressPools and writes Service status updates, and a DaemonSet of speaker pods on each node that announce assigned IPs to the physical network. Announcement is either BGP (via a from-scratch native Go BGP stack, a deprecated FRR sidecar mode, or the newer FRR-K8s API that generates FRRConfiguration CRs) or Layer2 (ARP/NDP responders with memberlist-based fast failover detection and deterministic speaker election). All user configuration flows through CRDs — IPAddressPool, BGPPeer, BGPAdvertisement, L2Advertisement, Community, BFDProfile, and ConfigurationState — validated by admission webhooks, with a configmaptocrs tool migrating legacy ConfigMap configuration to the CRD model. The controller/speaker split, a listener abstraction that delivers config changes to protocol handlers, and a common bgp.Session interface across backends give the architecture a clean, modular shape.
The bird-lg-go project is a Go implementation of a BGP looking glass, providing both a web frontend and a proxy service for interacting with BIRD routing daemons. It allows users to view BGP protocol status, look up routes, perform traceroute and whois queries, and visualize AS paths via a graphical interface. The frontend and proxy can be used independently or together, and are compatible with the original Python-based bird-lg project. The architecture consists of two main components: the frontend, which serves as a web interface and API endpoint, and the proxy, which handles communication with the BIRD daemon and executes traceroute commands. The frontend uses the proxy to retrieve data, which it then formats and presents to users via HTML templates or JSON API responses. The project emphasizes security through features like command restriction in the proxy and IP-based access control. Key technical strengths include the VRF socket binding abstraction for Linux systems, a robust WHOIS implementation that supports both external servers and local binaries, a traceroute module with automatic binary detection and concurrency control, and a reusable batch request pattern for parallel backend queries. The codebase is well-tested, uses modern Go practices, and maintains compatibility with various BIRD versions and operating systems.
This is a comprehensive command-line tool and self-hosted web server for network reconnaissance, written entirely in Bash. It performs ASN lookups, BGP statistics, RPKI validation, IP geolocation, IP reputation checks (via StopForumSpam, IPQualityScore, GreyNoise), Shodan InternetDB scanning for open ports and vulnerabilities, AS path tracing with detailed hop information, and more. The architecture is a monolithic Bash script (~7000 lines) that integrates numerous public APIs (RIPEStat, Team Cymru, pWhois, PeeringDB, CAIDA, ipinfo.io, ip-api, Cloudflare Radar, etc.) and command-line tools (mtr, whois, jq, curl, ncat). It can run in interactive mode, JSON output mode (as an API), or as an HTTP server (using ncat) that generates HTML reports with clickable links and a bookmarklet for browser integration. The code is well-structured for a shell script, with extensive error handling, caching of API responses, and support for API tokens to enhance functionality. While it is not modular in a traditional sense (everything is in one file), it demonstrates high craftsmanship in Bash and is actively maintained.