Postfix dns lookup and throttle?
Postfix experts, I am running Postfix 2.3.3 on a Centos 5.3 system. We are using it as our primary gateway for relaying email to many of our users at Google (in the cloud). The problem is that during heavier usage times, many messages seem to get queued and delayed due to Google's smtp server not being able to handle to many messages at one time (seemingly). So I have a couple questions that might help us address this problem. - how long does Postfix cache the IP address of dns names for email relaying purpose? Is this a variable that can be changed? - can Postfix be configured to back off from relaying messages, for example for 1 or 2 seconds when it receives deferrals from the receiving smtp server side? Thanks! Tim Tyler Network Engineer Beloit College
Re: Postfix dns lookup and throttle?
Tim Tyler wrote: Postfix experts, I am running Postfix 2.3.3 on a Centos 5.3 system. We are using it as our primary gateway for relaying email to many of our users at Google (in the cloud). The problem is that during heavier usage times, many messages seem to get queued and delayed due to Google’s smtp server not being able to handle to many messages at one time (seemingly). So I have a couple questions that might help us address this problem. - how long does Postfix cache the IP address of dns names for email relaying purpose? Is this a variable that can be changed? Postfix does not cache DNS lookups. - can Postfix be configured to back off from relaying messages, for example for 1 or 2 seconds when it receives deferrals from the receiving smtp server side? See: http://www.postfix.org/TUNING_README.html#mailing_tips and following sections on frequency of deferred attempts. Beware! tuning queue parameters often results in poorer performance than the carefully-chosen defaults. -- Noel Jones Thanks! Tim Tyler Network Engineer Beloit College
