Depending on the configuration of your SMTP provider's server, it might allow for per email domain configuration settings, such as how many emails may be relayed out per email account per domain, or per domain, or what gets amended or stripped from the emails, ie, headers and message body. In your case, there might be a chance you may ask the admin to create some entries that change outgoing SMTP behavior for your emails. This includes emails that were "piped in" via the command line, or via compiled perl modules that interface with the system. (Like your perl script using Mime::Lite) There are usually many points where you might be able to process outgoing emails before relaying out.