Internet mail (Email) uses several protocols. SMTP is used to send mail. And POP and IMAP are used by client email programs to retrieve email from a server for reading.

NetKernel provides support for the SMTP protocol with client tools and the NetKernel application functioning as a client to an SMTP server. NetKernel provides support for the POP and IMAP protocols through a transport. All mail tools tools are provided by the module mod-smtp.