On paid Plans, Site code can connect to the internet: payment providers, email services, APIs.
Always blocked, for every Site:
- Private and internal networks, including Haume's own servers.
- Outgoing mail on port 25. Use an email service on port 465 or 587.
Trial Sites can't make outbound connections at all. The built-in contact form still works, because it uses Haume's own mail service.