Local Mail Server (Postfix)

EAS Station can install and manage a Postfix mail transfer agent directly on the host server. Once running, it acts as a local send-only SMTP relay — no external email provider is required.

!!! tip "Easiest path for most users" If you just want reliable outbound email and don't want to manage a full mail server, use a free authenticated relay instead. Brevo, SendGrid, and Resend all have free tiers that work on Vultr without any support tickets.

Overview

Setup via the Admin UI

No terminal access required. All steps are performed in the browser.

1. Open Mail Server Settings

Go to Settings → Mail Server in the EAS Station navigation bar.

2. Install Postfix

If Postfix is not yet installed, the page shows an Install Postfix button. Click it. EAS Station runs apt-get install postfix in the background. Installation takes about 30–60 seconds depending on connection speed. The page reloads automatically when done.

3. Configure

Two fields are required:

Mail Hostname (FQDN) : The fully-qualified domain name this server will use when introducing itself to remote mail servers. Example: mail.yourdomain.com.

This **must match** your server's PTR (reverse-DNS) record for reliable delivery.
EAS Station auto-detects the current system hostname as a starting point.

Sender Address : The From: address on all outbound alert emails. Example: alerts@yourdomain.com.

The domain should have an SPF record that includes your server's IP.

Click Apply Configuration & Restart. EAS Station writes /etc/postfix/main.cf and restarts the Postfix service.

4. Connect to EAS Station Notifications

Once Postfix is running (green Port 25 Open badge), click:

Use Postfix for Alert Emails

This sets the notification mail URL to smtp://localhost:25 directly in the database. You can also click Open Notification Settings to review the full email configuration.

5. Send a Test Email

Enter a recipient address and click Send Test. Check your spam folder if the message doesn't arrive within a few minutes.

Vultr-Specific Setup

Unblock Port 25

Vultr blocks outbound port 25 by default on all new instances. You must request it to be unblocked before Postfix can deliver mail directly.

1. Log into my.vultr.com.
2. Open a Support ticket with subject: "Request to unblock SMTP port 25".
3. Include your instance IP and a brief description of the use case (e.g., "Self-hosted emergency alert notification system").
4. Vultr typically responds within a few hours for accounts in good standing.

!!! note If you don't want to wait or deal with this, use a free relay service instead — they operate on port 587 and work immediately.

DNS Records

For mail to reach recipients without being flagged as spam, configure the following DNS records for your sending domain:

PTR (Reverse DNS)

Set in the Vultr control panel:

1. Go to Products → Instances → your instance.
2. Click Settings → IPv4.
3. Set the Reverse DNS field to match the hostname you configured in EAS Station (e.g., mail.yourdomain.com).

SPF (Sender Policy Framework)

Add a TXT record to your domain's DNS:

v=spf1 ip4:YOUR_SERVER_IP ~all

Replace YOUR_SERVER_IP with your Vultr instance's public IPv4 address.

MX Record (Optional)

Not required for a send-only server, but some spam filters check for a valid MX record:

mail.yourdomain.com  MX  10  mail.yourdomain.com

Postfix Configuration Details

EAS Station writes the following main.cf to /etc/postfix/main.cf:

# Postfix main.cf — managed by EAS Station
myhostname = mail.yourdomain.com    # ← your configured hostname
myorigin   = $myhostname

# Only accept local delivery
mydestination = $myhostname, localhost.$mydomain, localhost

# Direct internet delivery — no relay
relayhost =

# Loopback trust only
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

# Bind to loopback only — not exposed externally
inet_interfaces = loopback-only
inet_protocols  = all

# Opportunistic TLS on outbound connections
smtp_tls_security_level = may
smtp_tls_loglevel       = 1

# Enforce sender address
sender_canonical_maps = static:alerts@yourdomain.com  # ← your From address

Authenticated Smart Relay (Optional)

If you prefer Postfix to relay through a third-party SMTP service rather than delivering directly (e.g., because port 25 is blocked or you want better deliverability), you can configure a smart relay. This is not currently available via the GUI — it requires editing /etc/postfix/main.cf directly.

Add these lines after applying the base configuration:

# Smart relay via Brevo (example — substitute any provider)
relayhost = [smtp-relay.brevo.com]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_security_level = encrypt

Create /etc/postfix/sasl_passwd:

[smtp-relay.brevo.com]:587  your@email.com:YOUR_SMTP_KEY

Then run:

sudo postmap /etc/postfix/sasl_passwd
sudo systemctl restart postfix

Useful Commands

View the mail queue:

mailq

Flush the queue (retry all deferred messages):

postqueue -f

View live Postfix logs:

journalctl -u postfix -f

Check Postfix configuration:

postfix check

Troubleshooting

"Port 25 Closed" after Apply

• Postfix may still be starting up — click Refresh after 10–15 seconds.
• Check logs: journalctl -u postfix -e
• Verify inet_interfaces = loopback-only is set (only listens on 127.0.0.1, but the port should still be reachable from EAS Station).

Mail is being deferred / rejected

• Confirm Vultr has unblocked port 25 on your account.
• Verify your PTR record matches myhostname exactly.
• Check the mail log: journalctl -u postfix -f

Mail going to spam

• Add the SPF TXT record for your domain.
• Ensure the PTR record is set correctly in Vultr.
• For better deliverability, consider adding DKIM signing via opendkim (advanced — not currently managed by EAS Station).