qmail-verify

a secure, reliable, efficient, simple message transfer agent

Debian Debian
RUN apt-get update && \ apt-get install -y qmail
Ubuntu
RUN apt-get update && \ apt-get install -y qmail
image/svg+xml Kali Linux
RUN apt-get update && \ apt-get install -y qmail
Raspbian
RUN apt-get update && \ apt-get install -y qmail
click the source code to copy install qmail-verify on any operating system with command-not-found.com