Core Configuration Files

The Haraka core reads some configuration files to determine a few actions:

  • loglevel

    Can contain either a number or a string. See the top of logger.js for the different levels available.

  • smtp.yaml or smtp.json

If either of these files exist then they are loaded first after loglevel. This file is designed to use the JSON/YAML file overrides documented in to optionally provide the entire configuration in a single file.

  • log_timestamps

    If this contains a 1 (or other truthy value), will prepend a timestamp to log lines. Note this only affects log lines sent via console.log, not the actual content sent to log hooks, so logging via syslog for example will not include a timestamp.

  • databytes

    Contains the maximum SIZE of an email that Haraka will receive.

  • plugins

    The list of plugins to load

  • smtp.ini


    • port - the port to use (default: 25)
    • listen_address - default: (i.e. all addresses)
    • inactivity_time - how long to let clients idle in seconds (default: 300)
    • nodes - if cluster is available, specifies how many processes to fork off. Can be the string “cpus” to fork off as many children as there are CPUs (default: 0, which disables cluster mode)
    • user - optionally a user to drop privileges to. Can be a string or UID.
    • group - optionally a group to drop privileges to. Can be a string or GID.
    • ignore_bad_plugins - If a plugin fails to compile by default Haraka will stop at load time. If, however, you wish to continue on without that plugin’s facilities, then set this config option
    • daemonize - enable this to cause Haraka to fork into the background on start-up (default: 0)
    • daemon_log_file - (default: /var/log/haraka.log) where to redirect stdout/stderr when daemonized
    • daemon_pid_file - (default: /var/run/ where to write a PID file to
    • spool_dir - (default: none) directory to create temporary spool files in
    • spool_after - (default: -1) if message exceeds this size in bytes, then spool the message to disk specify -1 to disable spooling completely or 0 to force all messages to be spooled to disk.
  • me

    A name to use for this server. Used in received lines and elsewhere. Setup by default to be your hostname.

  • deny_includes_uuid

    Each connection and mail in Haraka includes a UUID which is also in most log messages. If you put a 1 in this file then every denied mail (either via DENY/5xx or DENYSOFT/4xx return codes) will include the uuid at the start of each line of the deny message in brackets, making it easy to track problems back to the logs.

    Because UUIDs are long, if you put a number greater than 1 in the config file, it will be truncated to that length. We recommend a 6 as a good balance of finding in the logs and not making lines too long.

  • banner_includes_uuid

    This will add the full UUID to the first line of the SMTP greeting banner.

  • early_talker_delay

    If clients talk early we punish them with a delay of this many milliseconds default: 1000.

  • plugin_timeout

    Seconds to allow a plugin to run before the next hook is called automatically default: 30

    Note also that each plugin can have a config/<plugin_name>.timeout file specifying a per-plugin timeout. In this file you can set a timeout of 0 to mean that this plugin’s hooks never time out. Use this with care.

    If the plugin is in a sub-directory of plugins, then you must create this file in the equivalent path e.g. the queue/smtp_forward would need a timeout file in config/queue/smtp_forward.timeout

  • smtpgreeting

    The greeting line used when a client connects. This can be multiple lines if required (this may cause some connecting machines to fail - though usually only spam-bots).

  • max_received_count

    The maximum number of “Received” headers allowed in an email. This is a simple protection against mail loops. Defaults to 100.

  • max_line_length

    The maximum length of lines in SMTP session commands (e.g. RCPT, HELO etc). Defaults to 512 (bytes) which is mandated by RFC 5321 § Clients exceeding this limit will be immediately disconnected with a “521 Command line too long” error.

  • max_data_line_length

    The maximum length of lines in the DATA section of emails. Defaults to 992 (bytes) which is the limit set by Sendmail. When this limit is exceeded the three bytes “\r\n “ (0x0d 0x0a 0x20) are inserted into the stream to “fix” it. This has the potential to “break” some email, but makes it more likely to be accepted by upstream/downstream services, and is the same behaviour as Sendmail. Also when the data line length limit is exceeded transaction.notes.data_line_length_exceeded is set to true.

  • outbound.concurrency_max

    Maximum concurrency to use when delivering mails outbound. Defaults to 100.

  • outbound.disabled

    Put a 1 in this file to temporarily disable outbound delivery. Useful to do while you’re figuring out network issues, or just testing things.

  • outbound.bounce_message

    The bounce message should delivery of the mail fail. See the source of. The default is normally fine. Bounce messages contain a number of template replacement values which are best discovered by looking at the source code.

  • haproxy_hosts

    A list of HAProxy hosts that Haraka should enable the PROXY protocol from. See

  • strict_rfc1869

    When enabled, this setting requires senders to conform to RFC 1869 and RFC 821 when sending the MAIL FROM and RCPT TO commands. In particular, the inclusion of spurious spaces or missing angle brackets will be rejected.

    to enable: echo 1 > /path/to/haraka/config/strict_rfc1869 to disable: echo 0 > /path/to/haraka/config/strict_rfc1869