SMTP server: installation and configuration with Windows Server - RDR-IT
GitHub - toorop/tmail: Golang SMTP server
GitHub - mocktools/go-smtp-mock: SMTP mock server written on Golang. Mimic any 📤 SMTP server behaviour for your test environment with fake SMTP server .
net/smtp: in smtp.go, c.cmd(501, "*") takes long for server to respond. · Issue #18094 · golang/go · GitHub