chasquid is a production-grade SMTP (email) server written in Go, focusing on simplicity, security, and ease of operation. It handles incoming and outgoing email with full support for modern email security standards including STARTTLS, DKIM signing and verification, SPF checking, MTA-STS enforcement, and per-domain security level tracking. The server architecture is modular: the main daemon delegates SMTP protocol handling to the internal/smtpsrv package, manages a persistent email queue via internal/queue, performs alias resolution with hooks via internal/aliases, and delivers mail either locally through an LMTP-based MDA (cmd/mda-lmtp) or remotely via SMTP courier with TLS and MX fallback. Authentication integrates with Dovecot or a local user database using scrypt password hashing. Configuration is defined via protobuf text format, supporting hot reload of domains, users, and aliases without restart. The repository includes CLI tools for administration (chasquid-util), SMTP connectivity checking (smtp-check), and Dovecot authentication testing (dovecot-auth-cli). A comprehensive test suite covers unit, integration, and fuzz tests, with test data for DKIM, SPF, aliases, and various protocol edge cases. The repository also provides a Dockerfile for containerized deployment and extensive documentation in Markdown and man pages. While primarily an application, the codebase contains several well-designed internal packages that could be extracted for reuse, such as the network tracing library, safe I/O utilities, and OpenMetrics exporter.
SPFtoolbox is a web application for performing DNS and WHOIS lookups. It provides a user-friendly interface to query various DNS record types (A, AAAA, MX, TXT, SPF, DMARC, etc.), check blacklists, verify port connectivity, perform reverse DNS lookups, and retrieve WHOIS information. The application consists of a PHP backend that handles the lookup operations and a JavaScript frontend that manages the user interface and AJAX requests. The backend uses PHP's built-in DNS functions and integrates the phpWhois library for WHOIS queries.