ngIRCd

ngIRCd is a lightweight, fully‑featured Internet Relay Chat (IRC) daemon written in C that targets both small private networks and larger multi‑server deployments. From a technical standpoint it implements the core IRC protocol (RFC 1459) while intentionally omitting legacy “quirks” that would bloat the code base. The daemon runs as a single binary with an extensible configuration file (ngircd.conf) that controls networking, security, user modes, and server topology. It can operate in a standalone mode or as part of an IRC network, establishing secure TLS links between servers and clients alike.

Architecture

• Language & Build: Pure C (C99‑compatible) with a minimal dependency set, enabling cross‑platform builds on Unix‑like systems and Windows via WSL or Cygwin. The source is heavily modularized: core networking, authentication, command parsing, and mode handling are isolated into separate modules to aid maintenance.
• Networking: Uses non‑blocking sockets with select()/poll() (or epoll on Linux) to support thousands of concurrent connections. IPv4 and IPv6 are supported natively, and the daemon can negotiate TLS via OpenSSL or LibreSSL for both client‑server and server‑server links.
• Authentication: Integrates with PAM for flexible user authentication, supports IDENT lookups, and can enforce password policies. User data is stored in-memory; persistence (e.g., for bans or channel lists) relies on simple flat files or optional database backends.
• Extensibility: A plugin architecture exposes hooks for custom command handlers and event callbacks. Developers can write shared libraries (*.so/*.dll) that the daemon loads at runtime, allowing custom authentication schemes, logging, or integration with external services.

Core Capabilities

• Command Set: Implements the full set of standard IRC commands (JOIN, PRIVMSG, KICK, etc.) plus popular channel/user modes (+o, +v, +s, +i).
• Server Networking: Supports server linking with optional cloaking (masking real IPs) and dynamic IP handling, making it suitable for geographically distributed networks.
• Security: TLS support is optional but recommended; the daemon can enforce client certificate verification. It also supports cloaking to obfuscate user hostnames from external servers.
• API & Webhooks: While ngIRCd itself does not expose a REST API, its plugin system can forward events to external services via sockets or HTTP. Existing plugins already provide IRC → Slack, Discord, or webhook integrations.

Deployment & Infrastructure

ngIRCd is designed for self‑hosting on a wide range of operating systems, including Linux distributions, BSD variants, macOS, and Windows (via WSL/Cygwin). It can be containerized easily: the binary plus a minimal ngircd.conf fit into a lightweight Alpine or Debian image. For high‑availability, administrators can run multiple instances behind a load balancer and use the built‑in server linking to maintain network continuity. The daemon’s low memory footprint (≈10 MB RAM on a busy node) and efficient event loop make it suitable for embedded devices or cloud VMs with limited resources.

Integration & Extensibility

The plugin API is intentionally straightforward: a shared library registers callbacks for IRC events (on_user_join, on_message, etc.). This allows developers to write custom logic in any language that can produce a shared library (C, Rust, Go with cgo). Many community‑maintained plugins exist—e.g., authentication backends (LDAP, SQL), anti‑spam filters, and bridge modules to other chat platforms. The configuration file itself is highly readable; administrators can enable or disable plugins via simple directives, and the daemon logs detailed diagnostics to aid debugging.

Developer Experience

ngIRCd offers a concise, well‑documented configuration format (ngircd.conf(5)) and comprehensive man pages. The source code is modern, with clear module boundaries and extensive comments, facilitating contribution. Community support is active on GitHub issue trackers and mailing lists; the project’s long history (over 24 years) ensures stability. The license is GPL‑v3, which may influence commercial deployment decisions but guarantees freedom to modify and redistribute.

Use Cases

• Private Team Chat: Small organizations can deploy a single ngIRCd instance for internal communication, leveraging PAM integration with corporate LDAP.
• Multi‑Server Networks: Hobbyists building a small IRC network (e.g., for a gaming community) can link several ngIRCd nodes across the internet, using TLS and cloaking to protect hostnames.
• Embedded Systems: Devices requiring lightweight chat capabilities (e.g., IoT hubs, routers) can run ngIRCd within a container or directly on the host.
• Bridge Services: Developers building bridges between IRC and modern messaging platforms can use ngIRCd as the core daemon and plug in HTTP/webhook adapters.

Advantages

• Performance & Footprint: The C implementation and event‑driven architecture deliver low latency and minimal resource usage.
• Flexibility: Modular design, plugin support, and PAM integration allow tailored deployments without rewriting the core.
• Portability: Compiles on a broad spectrum of Unix‑like OSes and Windows, making it suitable for diverse environments.
• Licensing: GPL‑v3 ensures the code remains free and open, encouraging community contributions while protecting user freedom.

In summary, ngIRCd provides a robust, extensible foundation for developers who need a lightweight