Forum OpenACS Q&A: Response to ns_sendmail stalls out
I started that thread msg_id=0001DG that mentions use qmail. We didn't. Instead, we use postfix.org and regularly send out over 12,000 messages in one loop through the db using ns_sendmail and other than slowing down the server for a while, it works great and has never stopped in over 9 months. (knock on wood!).