SMTP support on InterServer VPS instances

Posted on January 14th, 2024

TLDR: Any one dealing in SMTP is aware of abuse and spam, and aware that SPAM can lead to ip blacklisting at collateral damage. It should come as no surprise that SMTP is blocked by default and requires additional verification.

InterServer blocks outbound traffic on port 25 (SMTP) on all VPS’s by default. To create request to unblock these ports for a valid use case please provide:
* A statement outlining your plan for assuring that your account isn’t implicated in sending unwanted emails.
* Setting a server hostname pointing to the main IP of your vps instance and a valid reverse dns.

Please be aware: VPS’s which are for mailing only are disallowed on InterServer’s network ( a system who’s primary purpose is sending email over SMTP ). Interserver’s network is monitored through multiple feedback loops and may suspend, disable smtp or block a vps that has a high complaint ratio including servers that may be CAN-SPAM compliant. Running a single opt-in, opt-out only, or any other non-double opt-in mailing list may result in termination. We under stand web hosts may have clients who use email and we do not consider these set ups mail only.

Be aware that requests could be denied based on domain age, reputation, and a request must be made per each VPS meeting the above requirements.

Requests coming from free email accounts may be denied, or require further details to open the smtp service.