I own one of these temporary email sites and it’s actually pretty popular. Maybe too popular at the moment.

I bought a server just to handle the 30 million or so emails it is receiving.
I currently run sendmail, dovecot, spamassassin and awstats but I am not tied to it.

if you were to build a new mail server, what software would you use as your mail server? pop Server? Despam? Stats?

30mm emails over what time period? Daily?

5 or 10. And only 1 account and it gets popped every 30 seconds.

No relaying.