Increasing qmail sending limits

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  • Applies to: DV 4.0
    • Difficulty: Medium
    • Time Needed: 20
    • Tools Required: SSH, root or sudo access, vi knowledge


The default configuration for qmail on the DV servers may be considered relatively conservative if you are sending large amounts of email in a short period of time. This article will allow you to send emails more reliably while still maintaining compliance with servers which implement greylisting.


Before you start, this article has the following dependencies:

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To start, run the following commands, line by line:

Please verify that these setting have not already been customized, running the commands will overwrite any changes they have made. The following command will show you whether those files exist:

ls /var/qmail/control | egrep 'timeoutremote|timeoutsmtpd|concurrencyremote'
echo "120" > /var/qmail/control/timeoutremote
echo "120" > /var/qmail/control/timeoutsmtpd
echo "40" > /var/qmail/control/concurrencyremote

The default timeouts are set to 20 minutes, or 1200 seconds. So if the mail server on the other end is not responding, the outgoing email stays in qmail's remote queue for 20 minutes before it fails. By default, there are 20 outgoing slots for email so this can backup quickly. These settings also increase the number of emails which can be sent at one time to 40. These settings should be safe for all DV servers.

When you have made the changes, restart qmail with the following command:

/etc/init.d/qmail restart

Mail should now begin to process faster on your DV server.

Atmail Outgoing Sending Limits

If you're using Atmail on your DV server to send via webmail, you may also encounter an outbound mail limit that is built into Atmail.

To solve this separate (but similar) issue, you'll need to edit your Atmail configuration file, located at /var/www/atmail/libs/Atmail/Config.php on your DV server. Locate a line with the value "filter_max_msgs", and edit the 100 to match your requirements. Once done, save the file and future connections to Atmail will use this new sending limit.