Network and sending email
Your addresses
| Address | Its role |
|---|---|
| IPv4 address | your dedicated address, which belongs to your server alone: your domains, your certificates, your filtering rules and your reputation rest on it |
| IPv6 address | your server's public IPv6 address |
Both are shown in your server's card, VPS section of your client area.
All ports
Your dedicated IPv4 address receives traffic on all ports: a site on 80 and 443, SSH on 22, a WireGuard VPN on 51820/udp, an API on the port of your choice. Your firewall decides what your server exposes.
Your firewall
Open only what your services expose to the public. With ufw, on Ubuntu or Debian:
apt install ufw
ufw default deny incoming
ufw default allow outgoing
ufw allow 22/tcp # SSH
ufw allow 80/tcp # HTTP
ufw allow 443/tcp # HTTPS
ufw enable
ufw status verbose
Open the SSH port before enabling the firewall, to keep your access. On Windows Server, Windows Defender Firewall plays the same role.
Anti-DDoS protection
Always-on network filtering stops flood attacks before they reach your server, continuously and with no setup on your part.
Traffic
Your VPS Ultra has no monthly traffic limit.
Sending email
Two ways to do it, depending on your project.
Through an authenticated SMTP relay
Your applications send their email through an SMTP relay, on port 587 with STARTTLS: an address from your current email provider, or Simafri Suite, the professional email at your own domain name (see the Simafri Suite documentation). It is the simplest route, and it works from the moment the server goes into service.
Directly, from your own address
Your VPS Ultra can also send its mail itself, from your dedicated IPv4 address: a complete mail server, or an application that delivers its email without a relay. Direct sending is enabled on request, once your account is verified:
- Write to support with your server's name, the sending domain and the intended use.
- At the same time, request the reverse name (PTR) of your IPv4 address, for example
mail.my-company.com: receiving servers check it. - Publish your server's SPF, DKIM and DMARC records in your domain's DNS zone.
Your sending reputation then rests on your address: send to recipients who are expecting your messages, and handle unsubscribes and addresses in error.
Frequently asked questions
How do I check that my emails are properly signed?
Send a message to a mailbox you read and display its source: the Authentication-Results headers show spf=pass, dkim=pass and dmarc=pass when everything is in place.
Can my server reach external services?
Yes: your applications call APIs, package repositories and services all over the world, over IPv4 as well as IPv6.