For perl to be able to use your FirstClass server as the mail host, you need to install and configure the Sendmail.pm perl module.
Inside your /Library/Perl folder on your Macintosh, you will find one or more folders, named 5.xx In the most recent version, create a folder called Mail
Create a new directory in \Perl64\site\lib and call it mail
In this lesson, you were asked to download and extract the support files. Inside there, you will find the Sendmail.pm module. Copy this file to the mail directory that you have just created.
Open Sendmail.pm in a text editor and modify the single line that is shown above to add the name of your SMTP domain name or IP Address for your FirstClass/OTSW server. This is likely mail.somename.com