Notlshosts/FQDN

notlshosts/FQDN

man qmail-remote excerpt:

qmail-remote will not try TLS on servers for which this file exists (FQDN is the fully-qualified domain name of the server). ([[tlshosts/FQDN.pem takes precedence over this file however).

Stop TLS encryption for a particular domain:
  1) # nslookup -type=mx 'domain.tld'
       domain.tld     mail exchanger = 0 mx.domain.tld.
  2) # mkdir /var/qmail/control/notlshosts/
  3) # touch /var/qmail/control/notlshosts/mx.domain.tld

qmail-remote