Feizhou a écrit :
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?
It might be related to browser retrying the request several times because it is a long task don't you think? This could explain why there are several smtp connections. Anyway I reported the bug to phpbb bug tracking.
Yes the phpbb is modded, but not by me. I'm just hosting it on my dedicated server.