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//Cloudogu EcoSystem Docs

Configuration of the Postfix dogu

Prerequisite

Configuration options

The Postfix dogu is configured via the etcd registry. There are several ways to configure values in the registry. In short you can:

  1. configure Postfix dogu with cesapp edit-config postfix (recommended)
  2. update the configuration values using a blueprint
  3. manually adjust the keys with etcdctl

Configuration

All configuration keys for the Postfix dogu settings have the key prefix config/postfix/. The Postfix dogu provides the following settings:

Relay host

  • Configuration key path: relayhost
  • The next-hop destination of non-local mail
  • Is usually already set during the setup of the CES
  • The value must then be set before installing the Postfix. This can be done with the following command:

    etcdctl set /config/postfix/relayhost <value for the relay host>

SASL authentication

  • Path of the configuration key: sasl_username and sasl_password.
  • If both keys are present, SASL authentication is configured at startup.
  • Optional

SMTP TLS security level

  • Configuration key path: smtp_tls_security_level
  • The default SMTP TLS security level for the Postfix SMTP client
  • Optional

SMTP client RSA certificate

  • Configuration key path: smtp_tls_cert_file
  • Postfix SMTP client RSA certificate in PEM format
  • Optional
  • Encrypted

Postfix SMTP client RSA private key

  • Configuration key path: smtp_tls_key_file
  • Postfix SMTP client RSA private key in PEM format
  • Optional
  • Encrypted

CA certificates

  • Configuration key path: smtp_tls_CAfile
  • CA certificates of root CAs trusted to sign either remote SMTP server certificates or intermediate CA certificates
  • Optional

Additional Postfix SMTP client logging

  • Configuration key path: smtp_tls_loglevel
  • Enable additional Postfix SMTP client logging of TLS activity
  • Optional

Excluding ciphers

  • Configuration key path: smtp_tls_exclude_ciphers
  • List of ciphers or cipher types to exclude from the Postfix SMTP client cipher list at all TLS security levels
  • Optional

Mandatory ciphers

  • Configuration key path: smtp_tls_mandatory_ciphers
  • The minimum TLS cipher grade that the Postfix SMTP client will use with mandatory TLS encryption
  • Optional

SSL/TLS protocols

  • Configuration key path: smtp_tls_mandatory_protocols
  • List of SSL/TLS protocols that the Postfix SMTP client will use with mandatory TLS encryption
  • Optional

Bare newlines

  • Configuration key path: smtpd_forbid_bare_newline
  • Disables support for malformed line endings in SMTP. This fixes CVE-2023-51764 but could break (rare) clients that mis-implement SMTP.
  • Optional
  • Valid values: yes, no
  • Default value: yes

Client exclusions for bare newlines

Log Level

  • Configuration key path: logging/root
  • Content: Set the root log level for the Postfix dogu.
  • Data type: string
  • Valid values: ERROR, WARN, INFO, DEBUG
  • Default value: INFO

Physical memory limit

  • Configuration key path: container_config/memory_limit
  • Content: limits the memory (RAM) of the Docker container for the Postfix dogu.
  • Data type: Binary memory specification.
  • Valid values: integer followed by [b,k,m,g] (byte, kibibyte, mebibyte, gibibyte).
  • Example: 1750m = 1750 MebiByte

Physical swap limit

  • Configuration key path: container_config/swap_limit
  • Content: limits Docker container swap for the Postfix dogu.
  • Data type: Binary memory specification.
  • Valid values: integer followed by [b,k,m,g] (byte, kibibyte, mebibyte, gibibyte).
  • Example: 1750m = 1750 MebiByte