is there a way to limit amount of email per X amount of time to certain domains? for example I have large list of emails and I have thousands of emails for yahoo.com, but if I start sending them all at once yahoo will temporarily defer me thinking that I'm doing something that I'm not suppose to do, yet if I send out only 100 emails an hour they are ok with this volume, so how can I restrict sendmail to send only 100 emails an hour to yahoo.com?
There are two options:
1) If this is an actual server in your environment for users, and you're doing this from an application or a script, you should change your application or script to manage the number of emails you send over an allotted time. Otherwise, you'll cause adverse issues for your normal users.
2) You can run sendmail with
Example from manpage:
For more information about how to use sendmail, you can read the manual here: http://www.sendmail.org/~ca/email/man/sendmail.html
Yahoo actually limits number of mails per envelope generally above that of mails per hour. If you reduce the number of Yahoo addresses per individual mail, they will allow a lot more through per hour.