Managing Mail Limits The main.cf file contains several settings to manage mail limits. Limit Recipients This parameter limits the number of recipients for a single message. The default is 1000 set in the smtpd_recipient_limit setting. Message Size Limit The message size is restricted to 10 MB by default. This is a setting that you will need to consider disk space and the needs of users. This is set in the message_size_limit parameter. ...