7.8 Timeout Configuration

The SMTP timeouts used in callout sessions are configured via smtp-timeout statement:

Syntax

smtp-timeout type {
  connection interval;
  initial-response interval;
  helo interval;
  mail interval;
  rcpt interval;
  rset interval;
  quit interval;
}

Mailfromd Conf: smtp-timeout type

Declare SMTP timeouts of the given type, which may be ‘soft’ or ‘hard’.

Callout SMTP sessions initiated by polling functions, are controlled by two sets of timeouts: ‘soft’ and ‘hard’. Soft timeouts are used by the mailfromd milter servers. Hard timeouts are used by callout servers (see callout server). When a soft timeout is exceeded, the calling procedure is delivered an ‘e_temp_failure’ exception and the session is scheduled for processing by a callout server. The latter re-runs the session using hard timeouts. If a hard timeout is exceeded, the address is marked as ‘not_found’ and is stored in the cache database with that status.

Normally, soft timeouts are set to shorter values, suitable for use in MFL scripts without causing excessive delays. Hard timeouts are set to large values, as requested by RFC 2822 and guarantee obtaining a definite answer (see below for the default values).

Statements

The time argument for all smtp-timeout sub-statements is expressed in time interval units, as described in time interval specification.

smtp-timeout: connection time

Sets initial connection timeout for callout tests. If the connection is not established within this time, the corresponding callout function returns temporary failure.

smtp-timeout: initial-response time

Sets the time to wait for the initial SMTP response.

smtp-timeout: helo time

Timeout for a response to ‘HELO’ (or ‘EHLO’) command.

smtp-timeout: mail time

Timeout for a response to ‘MAIL’ command.

smtp-timeout: rcpt time

Timeout for a response to ‘RCPT’ command.

smtp-timeout: rset time

Timeout for a response to ‘RSET’ command.

smtp-timeout: quit time

Timeout for a response to ‘QUIT’ command.

Default Values

The default timeout settings are:

Mailfromd Conf: io-timeout time

Sets a general SMTP I/O operation timeout. This timeout is used as the default for entries marked with ‘I/O’ in the above table. The default is 3 seconds.