Att. -- Rafael Azevedo | IAGENTE Fone: 51 3086.0262 MSN: raf...@hotmail.com Visite: www.iagente.com.br
Em 08/01/2013, às 14:07, Viktor Dukhovni <postfix-us...@dukhovni.org> escreveu: > On Tue, Jan 08, 2013 at 01:59:14PM -0200, Rafael Azevedo - IAGENTE wrote: > >> But Witse, would you agree with me that error 4XX is (in general >> cases) a temporary error? > > It is a temporary error for *that* recipient. It is not a global > indication that the site is temporary unreachable. Nor is there > any indication how long one should wait, nor that waiting will make > things any better. Yes you're right. There is no indication of how long we should wait, thats why it would be very nice to have a parameter to determinate that (just like maximal_queue_lifetime) > > Generally, delaying deliver *increases* congestion, since more mail > arrives in the mean-time, and once delivery resumes the volume is > even higher. Thats exactly the problem. We have what I call as "mxcluster", which is a box with hundreds of postfix running, splitting the traffic between them. It helps but its not solving the major problem. > >> Why keep trying when we have a clear signal of a temporary error? > > Postfix does not "keep trying", it defers the message in question > and moves on to the next one. Your mental model of email queue > management is too naive. > > This is a very difficult problem, and there is no simple answer. Yes it tries the next message. But what about when it is to the same domain and also happens to get deferred? > >> Also, if we had a temporary error control (number of deferred >> messages by recipient), it would be easy to identify when postfix >> should stop trying at least for a while. > > Given an arrival rate of ~50k msgs/day, you need to send at least > 1 msg/sec to avoid growing an infinitely large queue. This is basic > arithmetic. Gowing slower does not work, your queue grows without > bound. Thats why we have multiple instances of postfix running, to split the traffic among them. > Let the recipients know that if they want to continue to receive > your email they should choose a new provider that is willing to > work with legitimate senders to resolve mail delivery issues. Then > stop sending them email. Yes and no. Some SMTPs get higher volumes of mail, but not the entire traffic centralized in only one smtp. > > -- > Viktor. Rafael
