Article ID: 1470, created on Oct 6, 2008, last review on May 11, 2014

  • Applies to:
  • Plesk

Cause

Such error may occur if there are too many connections to SMTP service occurred.

Resolution

1. Increase the maximum number of SMTP connections:

RedHat based OSes:

Edit /etc/xinetd.conf:
instances = 200


Debian:

Edit /etc/inetd.conf and set:

smtp stream tcp nowait.1000 root /var/qmail/bin/tcp-env tcp-env /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true

smtps stream tcp nowait.1000 root /var/qmail/bin/tcp-env tcp-env /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true

Also increase number of connections per minute for inetd /etc/rc.conf file, for example:
inetd_flags="-wW -R 5000"


FreeBSD:

Edit /etc/inetd.conf and set:

smtp stream tcp nowait/1000 root /usr/local/psa/qmail/bin/tcp-env tcp-env /usr/local/psa/qmail/bin/relaylock /usr/local/psa/qmail/bin/qmail-smtpd /usr/local/psa/qmail/bin/smtp_auth /usr/local/psa/qmail/bin/true /usr/local/psa/qmail/bin/cmd5checkpw /usr/local/psa/qmail/bin/true

smtps stream tcp nowait/1000 root /usr/local/psa/qmail/bin/tcp-env tcp-env /usr/local/psa/qmail/bin/relaylock /usr/local/psa/qmail/bin/qmail-smtpd /usr/local/psa/qmail/bin/smtp_auth /usr/local/psa/qmail/bin/true /usr/local/psa/qmail/bin/cmd5checkpw /usr/local/psa/qmail/bin/true

Also increase number of connections per minute for inetd /etc/rc.conf file, for example:
inetd_flags="-wW -R 5000"


2. Restart inetd/xinetd.

RedHat based OSes:
# /etc/init.d/xinetd restart

Debian/FreeBSD:
# /etc/init.d/inetd restart


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