> I tried smtp-sink on another port and found that phpbb was the cause of > the problem. > phpbb did several connections to the smtp-sink and sent multiple emails > with more than 50000 recipients instead of 3500. > When I sorted the smtp-sink output, I could see recipients duplicated > multiple times. > > Conclusion postfix works great! phpbb sucks! Now I wonder what is wrong with phpbb...is yours modified at all?