mjp
5-18-05, 10:08 AM
Some of our users have reported problems sending mail to @hotmail.com accounts. We have thoroughly investigated the issue, and the bottom line is that hotmail is simply a very overloaded system, and we have come to learn that many system administrators around the world are facing the same issues we are.
hotmail has 4 MX records, each of which has 4 round-robin IP addresses (and probably load balancing behind that). Our tests consisted of attempting to connect to every IP, both from within the PowWeb network and from several outside networks. What we found was a 31% failure rate on mail intended for hotmail, regardless of the network of origin.
We will be reconfiguring postfix (the software that runs on the mail servers) to use "cached connections," which has proven to be successful in reducing the failure rate for mail sent to hotmail on some networks. We may also apply separate rules in the postfix configuration to help insure that mail sent to busy networks such as hotmail or yahoo is delivered. The reconfiguration of the mail servers is not a trivial process however, so it will have to be tested and implemented slowly so we can catch any potential problems.
In the meantime, all we can suggest is resending mail bounced from hotmail. We will do everything we can to insure that the mail sent from our servers is delivered to hotmail, but ultimately this is a hotmail issue, one that is out of our control.
hotmail has 4 MX records, each of which has 4 round-robin IP addresses (and probably load balancing behind that). Our tests consisted of attempting to connect to every IP, both from within the PowWeb network and from several outside networks. What we found was a 31% failure rate on mail intended for hotmail, regardless of the network of origin.
We will be reconfiguring postfix (the software that runs on the mail servers) to use "cached connections," which has proven to be successful in reducing the failure rate for mail sent to hotmail on some networks. We may also apply separate rules in the postfix configuration to help insure that mail sent to busy networks such as hotmail or yahoo is delivered. The reconfiguration of the mail servers is not a trivial process however, so it will have to be tested and implemented slowly so we can catch any potential problems.
In the meantime, all we can suggest is resending mail bounced from hotmail. We will do everything we can to insure that the mail sent from our servers is delivered to hotmail, but ultimately this is a hotmail issue, one that is out of our control.