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Documentation Index

Fetch the complete documentation index at: https://jetemail.com/docs/llms.txt

Use this file to discover all available pages before exploring further.

This guide will walk you through configuring Exim to use JetEmail as your smarthost for improved email deliverability and authentication.

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Prerequisites

  • Root access to your server
  • Exim mail server installed and running
  • JetEmail SMTP credentials from your dashboard

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Configuration Steps

1

Generate SMTP Credentials

Create a smarthost (or use an existing one) in your JetEmail dashboard.
2

Configure Authentication

Add the following to your Exim configuration file (typically /etc/exim4/exim4.conf.template or /etc/exim.conf):
# JetEmail Authentication
jetemail_login:
  driver = plaintext
  public_name = LOGIN
  client_send = : your_username : your_password
Replace your_username and your_password with your JetEmail SMTP credentials.
3

Configure Transport

Add the transport configuration:
# JetEmail SMTP Transport
jetemail_smtp:
  driver = smtp
  hosts_require_auth = *
  tls_tempfail_tryclear = true
  headers_add = X-AuthUser: your_username
  hosts_try_chunking =
  hosts_try_fastopen =
  dkim_domain = ${lc:${domain:$h_from:}}
  dkim_selector = default
  dkim_private_key = /path/to/dkim/private/${dkim_domain}
Update the dkim_private_key path to match your DKIM key location.
4

Configure Router

Add the router configuration to send mail via JetEmail:
# JetEmail Smarthost Router
send_via_jetemail:
  driver = manualroute
  domains = ! +local_domains
  ignore_target_hosts = 127.0.0.0/8
  transport = jetemail_smtp
  route_list = * relay.jetsmtp.net::25 randomize byname
  no_more
5

Optional: Configure SRS (Sender Rewriting Scheme)

For email forwarding scenarios, add SRS support:
# SRS Transport for forwarded emails
jetemail_forward_smtp:
  driver = smtp
  hosts_require_auth = *
  tls_tempfail_tryclear = true
  headers_add = X-AuthUser: your_username
  hosts_try_chunking =
  hosts_try_fastopen =
  dkim_domain = ${lc:${domain:$h_from:}}
  dkim_selector = default
  dkim_private_key = /path/to/dkim/private/${dkim_domain}
  return_path = ${srs_encode {SRS_SECRET} {$return_path} {$original_domain}}
  max_rcpt = 1
6

Test and Restart Exim

Test your configuration and restart Exim:
exim -bV  # Test configuration syntax
systemctl restart exim4  # Debian/Ubuntu
# OR
systemctl restart exim   # CentOS/RHEL

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Additional Configuration

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SPF Records

Don’t forget to update your SPF records to include JetEmail’s servers: 
v=spf1 include:spf.jetsmtp.net ~all
Learn more about email authentication.

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Domain Authentication

For enhanced security and deliverability:
  • Configure Domain Lockdown to prevent domain spoofing
  • Set up DMARC for email authentication
  • Ensure proper DKIM signing is configured

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Testing Your Configuration

After configuration, test your setup:
  1. Send a test email to an external address
  2. Check email headers for authentication details: 
    echo "Test message" | mail -s "Test Subject" test@example.com
  3. Monitor delivery in your JetEmail dashboard
  4. Verify SPF, DKIM, and DMARC alignment

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Troubleshooting

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Authentication Failures

  • Verify your SMTP credentials are correct
  • Ensure your account is active and in good standing
  • Check that authentication headers are properly configured

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Connection Issues

  • Verify ports 25 or 587 are open in your firewall
  • Test connectivity to relay.jetsmtp.net: 
    telnet relay.jetsmtp.net 25
  • Check TLS configuration

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Configuration Errors

  • Check Exim logs for error messages: 
    tail -f /var/log/exim4/mainlog  # Debian/Ubuntu
tail -f /var/log/exim/main.log  # CentOS/RHEL
  • Verify configuration syntax with exim -bV

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Control Panel Integration

If you’re using a control panel, consider using our automated solutions instead: For additional support, contact our team or visit our Discord community.