Ports and networking

KVM 1, KVM 2 and custom sizes share a public IPv4: those guests live behind NAT. KVM 4 and KVM 8 include a dedicated IPv4. IPv6 is not available on our platform.

The 20-port block

Each NAT guest gets a contiguous block of twenty forwarded ports on the public address. SSH is the first port of that block — the -p value in the dashboard. Connect to the guest hostname, not the private 10.10.10.x address. The remaining nineteen forward to the same guest for HTTP, n8n, agent UIs, or whatever you bind. You do not receive the rest of the TCP range on the shared IP.

ssh -p <ssh-port> root@vmN.box.scalemaxcloud.com

Port 25

Outbound SMTP (TCP port 25) is blocked by default. That is an anti-spam measure. We open it on request when you have a specific, lawful use. Opening it is revocable, not a plan feature. The Acceptable Use Policy bans unsolicited bulk mail whether or not port 25 is open.

Dedicated IPv4

The Dedicated IPv4 add-on replaces shared NAT with your own public address: every inbound port, no twenty-port ceiling. KVM 4 and KVM 8 include it; on other plans, buy it at checkout or later from add-ons. The address is set up automatically and at once: when a new server is ready, or a minute after you pay for the add-on on an existing one. If no address is free at that moment, it is set up within 24 hours, by hand; until then the add-on shows as waiting for us on the add-ons page, and the server works on the shared address. When it is done, the server's Overview shows the address and its SSH command, ssh root@<address> on port 22. Every port on the address reaches your server; use the firewall to choose which ones are open. The shared hostname and its ports keep working too.