I have a client who needs to send 600+ (his whole contact list) email every morning at once. My mail server is Ubuntu 14.04.1 LTS running postfix with dovecot. Now I'm interested in ideas how to handle this and what to watch out for. A few questions: Can this 600+ email at once crash my server? Can this mass email sending blacklist my server as a spam server? Is there max send mail number per minute/hour that I have to be aware?
No. That's possible. But as long as your custmer ensured that all these users really want his email (double op-in) then there should be no major problems and 600 emails are not that many. Watch your mail.log, you will see when other servers block you for sending too fast.
ok... it's more like 2000 mail at once. Can I on the server side configure that it breaks this 2000 email into 100-200 mail every 2-5 seconds?
The email client should devide it into chunks and take care to wait a bit between them. Most mass mail capavle clients and software like newsletter plugins for e.g. WordPress can do that.
Ok, you guys except Till, have had a nice off topic rant. But I still did't get a awnser on how to limit on the server side or is it only possible with the mail clients. Example that a client creates a site and uses phpmailer for mass mailing. How can you prevent this? Or isn't it possible?
Postfix can send 600+ mails. But the destination may not accept all mails and delays the connection. You can define some rate_limits for postfix (in general or per domain): http://www.postfix.org/TUNING_README.html#mailing_tips https://wiki.deimos.fr/Postfix:_limit_outgoing_mail_throttling you can also use policyd/cluebringer: https://www.howtoforge.com/community/threads/limit-outgoing-number-of-messages-in-postfix.41131/