Hi Wietse, Thanks so much for your help!
I've already fixed the DNS problem. For testing pourposes, I'm using now another IP C CLASS that has no DNS fails. This is my test output - sending 5 emails per sender domain: # DOMAIN ZOOM4U.COM.BR (about 1 email per second) 12:56:10 - Sending email #1...OK 12:56:10 - Sending email #2...OK 12:56:11 - Sending email #3...OK 12:56:12 - Sending email #4...OK 12:56:13 - Sending email #5...OK # NOW USING IAGENTEMAIL.COM.BR (5 emails per second) 12:56:14 - Sending email #1...OK 12:56:14 - Sending email #2...OK 12:56:14 - Sending email #3...OK 12:56:14 - Sending email #4...OK 12:56:14 - Sending email #5...OK In both cases I'm using the same SMTP that uses another C class. See the difference? Thanks Rafael On Tue, Mar 15, 2011 at 12:26 PM, Wietse Venema <wie...@porcupine.org> wrote: > Rafael Azevedo: >> Hi Wietse, >> >> I thing I havent made myself clear. >> >> I have an email app running on BOX A and POSTFIX on BOX B. >> >> The BOX A connects to POSTFIX to send the messages. >> Thats exactly where the delay is. When the application tries to send >> the messages to POSTFIX, the APP sends about 2 messages per second TO >> POSTFIX using domain ZOOM4U.COM.BR. > >> The bottleneck is when POSTFIX RECEIVES THE CONNECTION from my >> application when using domain ZOOM4U.COM.BR. > > There are no "fast" or "slow" domain names in your logging. > Therefore, your conclusions are not supported by your evidence. > > What I do see is that your server can't deliver mail due to DNS > lookup error (50% likelihood of NXDOMAIN). > > Delays while delivering mail will result in delays while Postfix > receives mail. This is a built-in defense to prevent the sender > from overwhelming the Postfix queue. > > Therefore, you need to fix the delays with mail delivery (due ti > bad DNS or whatever). Then, there will be no delays while Postfix > receives mail. > > Wietse >