使用Bamboo发送邮件报错：DigitalOcean Droplet邮件服务器Postfix正常但适配器异常

Hey there! Let's figure out why your Bamboo SMTP setup is failing when the system-level mail command works perfectly on your DigitalOcean Droplet. Here are the most common issues and how to fix them:

The mail command uses Postfix's local delivery (often via Unix socket or trusted localhost access), but Bamboo connects over TCP—so mismatches here are the first thing to check:

• Server & Port: Ensure your Bamboo config points to localhost (or 127.0.0.1) and the correct port. Postfix typically listens on port 25 for local unauthenticated traffic, or 587 for submission with authentication. Double-check your config/config.exs (or runtime config) for:

  config :my_app, MyApp.Mailer,
    adapter: Bamboo.SMTPAdapter,
    server: "localhost",
    port: 25,
    # ... other settings
  

• Authentication: The mail command skips auth because it's a local system user, but if Postfix has smtpd_sasl_auth_enable = yes in main.cf, you need to add valid credentials to Bamboo (matching Postfix's SASL users). If auth isn't required, set username: nil and password: nil.
• TLS Settings: If Postfix doesn't enforce TLS on port 25, setting tls: :always in Bamboo will cause errors. Try tls: :never first for testing, or align it with Postfix's smtpd_tls_security_level value in main.cf.

Postfix might be blocking Bamboo's connection even though it lets the mail command through:

• mynetworks Configuration: In /etc/postfix/main.cf, make sure mynetworks includes 127.0.0.1/32 (localhost). This tells Postfix to trust connections from the local machine without auth. If it's missing, add it:

  mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
  

• Recipient Restrictions: Ensure smtpd_recipient_restrictions in main.cf has permit_mynetworks listed before restrictive rules like reject_unauth_destination. This ensures local connections are allowed first.

Get concrete details about what's failing:

• Enable Bamboo Debugging: Add debug: true to your Bamboo config. This will print the full SMTP conversation in your logs, showing exactly where the error occurs (e.g., EHLO rejection, auth failure).
• Check Postfix Logs: Run tail -f /var/log/mail.log (on Debian/Ubuntu) while trying to send via Bamboo. The logs will show Postfix's exact reason for rejecting the connection—look for lines like Client rejected: Access denied or SASL authentication failed.

Rule out Bamboo-specific issues by simulating the connection yourself:
Use telnet or nc to connect to Postfix directly:

telnet localhost 25
# Once connected:
EHLO localhost
MAIL FROM:<your_local_user@your_droplet_domain>
RCPT TO:<your_email_address>
DATA
Subject: Manual SMTP Test
This is a test email sent directly via SMTP
.
QUIT

If this manual test fails, the problem is in Postfix's configuration. If it succeeds, double-check every parameter in your Bamboo config for typos or mismatches.

内容的提问来源于stack exchange，提问作者Sh4dy