Dear Wietse, Thank again for your reply.
I've make the change on the master.cf and the main.cf. After restarted postfix, I've fewer errors. I've add this line in my main.cf: debugger_command = /usr/bin/strace -p $process_id -o /tmp/smtpd.$process_id & sleep 5 And updated my master.cf with that: sendercheck unix - n n - 0 spawn -D dunnopl unix - n n - 0 spawn -D When I've the error "command time limit exceeded", that is the strace of the process: http://pastebin.com/s3kne09r If the processus don't return a error, that was the starce: http://pastebin.com/GknKaMMx I find a change a the line 62 on the PastBin ... But I can't understand why ... Do you have an idee what's I can check ? Bests Regards and again thank for your time, Damien