Knowledge base

Authentication

• Authenticate clients using X.509 certificates
• Implement a custom SASL authentication mechanism
• Restrict SASL users to certain sender domains

Signing and validation

• Signing with S/MIME
• Signing with BATV
• Signing with DKIM
• Deploying DMARC

Delivery

• Scripted routing
• How to deliver using LMTP
• In-line delivery
• Outbound deliverability
• Using HAProxy for sharing outbound IP addresses
• Enable the DSN extensions

See all 7 articles

TLS

• Setting up Let's Encrypt for Halon
• Use required TLS for inbound and outbound traffic

Logging

• Remote logging to Elasticsearch
• Remote syslog to Logstash

Monitoring

• Monitoring with Prometheus
• Monitoring with Slack

Integration

• How to query a REST API effectively
• cPanel
• WHMCS

Threat protection

• Supported anti-spam engines
• Supported anti-virus engines

Miscellaneous

• RFC & standards compatibility
• High availability and load balancing
• How to implement recipient filtering
• Check if the sender domain exists
• Rate limiting
• SPF

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