Protecting Your IP Reputation, Preventing Abuse, and Enabling On-Request Access
At HostEONS, we prioritize network stability, IP reputation, and the safety of all our users. That’s why outgoing connections on Port 25 (SMTP) — the standard port for sending emails — are blocked by default on all VPS plans.
This might sound restrictive at first, but it’s actually a common best practice followed by many reputable hosting providers. Let’s explore why this matters and how we handle legitimate email sending needs.
🧠 What Is Port 25 Used For?
Port 25 is traditionally used for sending email over the Simple Mail Transfer Protocol (SMTP). If your server is sending outbound emails — whether from a web app, newsletter system, or mail server — it likely uses Port 25 (or alternatives like 465 and 587).
However, Port 25 is also the most abused port on the internet for spam and botnet activity.
❌ Why Port 25 Is Blocked by Default
1. Preventing Spam from Compromised VPS Instances
Most VPS users do not run a mail server, but if a VPS is compromised or misconfigured, attackers can exploit Port 25 to send spam.
This leads to:
- IP blacklisting (Spamhaus, SORBS, etc.)
- Mail delivery issues for all users sharing the subnet
- Service suspensions or reputation penalties
2. Avoiding Open Relay Misconfigurations
Even experienced users sometimes set up mail servers without authentication or misconfigured relays. This can turn the VPS into an open SMTP relay, allowing anyone on the internet to send email through it — a magnet for spammers.
3. Preventing Abuse via VPNs/Proxies
Some customers use their VPS as a VPN or proxy. If their own machine is infected with malware or spyware, the malware might use the VPN tunnel or proxy to spam through the VPS IP, again leading to blacklisting.
4. Protecting Our IP Space for Everyone
Once an IP gets listed on major spam blocklists, it can affect not just one customer — but the entire network or IP range. Preventing abuse ensures:
- High IP reputation
- Better deliverability for all users
- Fewer disruptions from abuse reports or RBL listings
✅ Need Port 25 Open? We’ve Got You Covered
We understand that legitimate use cases exist, such as:
- Running your own mail server (Postfix, Exim, etc.)
- Sending system alerts or transaction emails
- Hosting a mail relay with proper authentication
💬 Just Open a Ticket
If you need Port 25 enabled:
- Submit a request via our Client Portal
- Include brief details on how you plan to use email
- We’ll evaluate and enable Port 25 on a case-by-case basis for legitimate use
🛡️ Best Practices When Sending Mail from a VPS
If you do plan to send email from your VPS:
- Never use it for marketing or newsletter blasting
- Use proper authentication (SPF, DKIM, DMARC)
- Avoid open relays — always require SMTP auth
- Monitor logs and limit outbound email rates
- Consider using third-party SMTP relays like Amazon SES, Mailgun, or SendGrid
🚀 Summary
At HostEONS, Port 25 is blocked by default to protect all customers from IP reputation damage and network abuse.
We’re happy to enable it for users who demonstrate a responsible, legitimate use case.