On Mar 25, 2010, at 10:13, Tom Hendrikx wrote: > David Michard wrote: >> we are having more and more problems with >> very conservative SMTP servers enforcing a low number of simultaneous >> connections from a single IP address. Our subscribers wish to receive >> their email as soon as possible so delaying the email for a few hours >> is not an option. > > So actually you are trying to solve the other mail servers trouble. Did > you contact (some of) them to get you whitelisted?
Here's what I did when I had a similar issue with sendmail: I reconfigured sendmail such that all mailers are considered expensive. In sendmail, what this does is: new messages are only queued, and messages are sent only during a queue run. This has the effect of using a single connection to send the messages. Previously our several chatty servers would use dozens of simultaneous connections, and that irritated the admin who ran the corporate mail server, because it was effectively a low-grade DoS attack. Using this method means that some emails are delayed, but that overall there is a net increase in the speed of delivery of email. I don't know if postfix has a similar feature, but if it does, that's what I'd implement. Daniel
