Firewall on Zerops
Keywords
firewall, ports, nftables, tcp, udp, blocked ports, smtp port, port restriction, allowed ports
TL;DR
Zerops uses nftables with restricted TCP ports 1-1024 (only 22, 53, 80, 123, 443, 587 allowed); UDP and ports 1025-65535 are unrestricted.
TCP Ports 1-1024 (Restricted)
| Port | Protocol | Status |
|---|---|---|
| 22 | SSH | Allowed |
| 25 | SMTP | Blocked (spam prevention) |
| 53 | DNS | Allowed |
| 80 | HTTP | Allowed |
| 123 | NTP | Allowed |
| 443 | HTTPS | Allowed |
| 465 | SMTPS | Blocked (deprecated) |
| 587 | SMTP/STARTTLS | Allowed |
| All others | — | Blocked |
UDP Ports
No restrictions on any UDP port.
TCP Ports 1025-65535
No restrictions.
Direct Port Access Firewall
For services with direct port access enabled:
- Configure blacklist or whitelist rules per port
- Available on ports 10-65435
- Protocols: TCP, UDP
Port Modification
Contact support@zerops.io with Project ID + Organization ID to request changes to restricted ports.
Gotchas
- Port 25 is permanently blocked: Use port 587 with STARTTLS for email sending
- Port 465 is blocked: Legacy SMTPS — use 587 instead
- Cannot self-service unblock: Must contact Zerops support for port exceptions
See Also
- zerops://guides/public-access
- zerops://guides/smtp
- zerops://guides/networking