MIME::Lite says it uses sendmail

... or SMTP, as explained by GrandFather in Re: MTA for Perl.

But: sendmail (the executable) is not always Sendmail (the mail server). Yes, Sendmail is old (and has a long list of security problems), and in fact it is so old that its main executable sendmail has become a de facto standard. That is why many other mail servers come with a sendmail command that works as a drop-in replacement for the real sendmail from Sendmail. Usually, the replacement does not implement all commands and options, but only as much as needed to get mails sent out. The replacement sendmail is either a dedicated helper, or it is just a symlink to the main executable.

• Exim supports being called "sendmail" and some other names, this is documented in The Exim command line.
• Postfix has a dedicated sendmail program for Sendmail compatibility that supports being invoked as sendmail, mailq, and newaliases.
• qmail also has a sendmail executable.
• Courier has a dedicated sendmail command.
• Even the very minimal Nullmailer has a dedicated sendmail executable.

I think that Nullmailer is a very useful package if you already have a working mailserver, either locally or at your provider, and need a working mail system on a local machine. It just delegates EVERYTHING to that working mailserver ("smarthost") except for collecting mails that will be passed to the smarthost for delivery. I use it a lot on several virtual machines to connect to the "real" mailserver in the network.

Alexander

(Changed wording a few times in the first few minutes after posting.)