Can I use DKIM verification without DKIM signing?

You can disable DKIM signing in amavisd config file, then restart amavisd service:

$enable_dkim_signing = 0;

Amavisd config file could be one of below:

  • RHEL/CentOS/OpenSuSE: /etc/amavisd.conf
  • Debian/Ubuntu: /etc/amavis/conf.d/50-user
  • FreeBSD: /usr/local/etc/amavisd.conf

Also, iRedMail has its own support forum: http://www.iredmail.org/forum/ You can always get quick response in the forum.