By default, on all our VPS services, port 25 is closed to prevent spam. You can open port 25 in the firewall settings of your service. Go to the 'Service' menu, click on the 'Manage' button next to your VPS service, and then select 'Firewall settings'.

Important Note for Firewall Modifications: You must have paid for at least 30 days of service to be able to modify the firewall settings of your VPS. If you pay for shorter periods, port 25 will remain blocked, and you will not be able to change any firewall rules.

After opening port 25, you must also ensure that the Reverse DNS (rDNS) address of your IP and your mail sending server are configured properly.

Additionally, for successful email delivery, especially to major providers like Gmail, you must correctly configure the SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) records for your email sending domain. Without these, your emails may be blocked as unauthenticated.

• SPF: An SPF record specifies which mail servers are authorized to send email on behalf of your domain.
• DKIM: A DKIM record adds a digital signature to your outbound emails, allowing recipients to verify that the email was sent by the domain owner and was not altered in transit.

For instructions on how to set up SPF and DKIM, please refer to your domain's DNS management interface or consult relevant online guides.

If you are found sending SPAM, port 25 on your VPS will be disabled again. If this happens multiple times, the system will permanently disable port 25 on all your current and future VPS services, and neither you nor customer support will be able to remove this blocking.