Open the machine → Network tab.
Floating IPs
The Floating IPs panel lists every public address routed to this machine. A floating IP belongs to your organization rather than to the machine, so you can move it to another server later without changing the address — see Floating IPs for the full model.
- Click Add IP to attach another address. Only IPs in the same location as the machine can be attached.
- The primary IP can't be removed; it's the address the machine boots with.
- DDoS Protection status per IP is shown here, and links through to DDoS Mitigation.
Reverse DNS (rDNS)
Set a PTR record inline for each IP, for example mail.example.com. This matters most for outbound mail: many receiving servers reject or spam-folder mail from an IP whose reverse lookup doesn't resolve, or doesn't match the sending hostname.
Private network
Attach the machine to a private network so it can talk to your other servers over internal addresses instead of the public internet.
Pick a network from Select a network and click Attach. The network must already exist in the same location as the machine — if the dropdown is empty, create one there first. Detach removes it.
NoteAfter attaching or detaching a private network, restart the machine for the change to take effect.
Blocked SMTP ports
Outgoing traffic to ports 25 and 465 is blocked by default on all Cloud Servers, over IPv4 and IPv6. Spammers routinely abuse cloud infrastructure to send mail, so blocking these by default is standard practice across the industry, and it's what protects the reputation (and deliverability) of the whole IP range.
Use port 587 instead. It's the industry-recommended submission port for sending mail through an external delivery provider. For the overwhelming majority of applications this is the right answer.
Check whether your ports are open
The Blocked Ports card lists each IP address of the machine, IPv4 and IPv6, with the state of ports 25 and 465:
| Badge | Meaning |
|---|---|
| Blocked | Outgoing connections to ports 25 and 465 from this IP are dropped. This is the default for every new IP. |
| Open | Ports 25 and 465 have been unblocked for this IP after an approved request. Mail sent from this address can reach other servers directly. |
The state is set per IP address, not per server: if your machine has several IPs, each one shows its own badge, and only the approved ones are open. Make sure your mail software sends from an IP marked Open — a server with an open IPv4 and a blocked IPv6 will fail to deliver over IPv6, so either request both or bind your mail software to the open address.
When every IP is open the card says so and the Request Unblocking button disappears. While any IP is blocked the button stays.
Request unblocking
If you genuinely need direct SMTP, use Request Unblocking on this tab to open a ticket. Say which IPs you want opened. Requests are reviewed case by case and require:
- The machine to have completed at least one full billing cycle
- The first invoice to be paid
- A clear description of the use case, the software that will send mail, and confirmation that it complies with anti-spam policy
Once the request is approved the badge of that IP changes to Open. Reload the page if you already had it open.
WarningThe unblock belongs to the IP address. If you release the IP back to the pool, or destroy the server it's on, ports 25 and 465 are closed again for that address. A new IP always starts Blocked, even on a server whose other IPs are open.