Qmail

On a Plesk server, the maximum size for an individual e-mail sent through qmail is unlimited.

I really dislike qmail.

If you have a new Plesk installation and the following option is greyed out in Server -> Mail:

I stumbled upon this peculiar bounce message recently while working on a server:

I stumbled upon a server running Plesk 8.

One of my biggest beefs with Plesk’s e-mail handling is the lack of server-side filtering.