According to Earthlink and RFC2821, we shouldn't be forwarding email to the destination's A-record in the event that we can't contact one of their MX records. I'm pretty sure I've witnessed this behavior before. Is this a setting I can configure?
Thanks, Gabe Monroy, MCSE, CISSP Senior Systems Engineer - Intuit Eclipse Distribution Management Solutions 5340 Airport Blvd. Boulder, CO 80301 303-938-8801 x1158 http://eclipse.intuit.com ------------------ Hello, You are receiving this message in follow-up to a report received by the EarthLink Abuse Department. You may have submitted this report to a number of addresses including but not limited to [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED], or [EMAIL PROTECTED] The information below is of a technical nature and you may wish to forward this to your mailserver administrator in the event that you do not fulfill that role yourself. re. Our engineers have informed us that the error you are receiving: 550-EarthLink does not recognize your computer ([IP]) as connecting from an EarthLink connection. If this is in error, please contact technical support. ..is due to an improper MTA configuration with the host that is responsible for delivering outbound mail on your network. In a nutshell, the mailserver which attempted to deliver mail to the earthlink.net e-mail address was initially unable to successfully deliver the mail to the earthlink.net MX (more than likely due to high load on our end; no EarthLink MX host was available to accept the transaction at the moment of the delivery attempt), and so the EarthLink 'A' record was attempted by the sending mailserver. The earthlink.net 'A' record, however, forwards port 25 connections to our outbound SMTP servers. Unless the mailserver attempting the transaction maintains IP connectivity through the EarthLink network, delivery attempts through the 'A' record will consequently fail and the above quoted error message will be returned. The behavior exhibited by the sending mailserver, in this case, is not standard. According to RFC 2821, "Address Resolution and Mail Handling": "If one or more MX RRs are found for a given name, SMTP systems MUST NOT utilize any A RRs associated with that name unless they are located using the MX RRs; the "implicit MX" rule above applies only if there are no MX records present. If MX records are present, but none of them are usable, this situation MUST be reported as an error." Currently the EarthLink.net mx record resolves as follows: mx4.earthlink.net mx5.earthlink.net mx6.earthlink.net mx7.earthlink.net mx8.earthlink.net mx9.earthlink.net mxa.earthlink.net mxb.earthlink.net mxc.earthlink.net mxd.earthlink.net mxe.earthlink.net mx1.earthlink.net mx2.earthlink.net mx3.earthlink.net You may wish to verify that you are able to successfully resolve this record through your nameservers, and that you can successfully route to these hosts. Our engineers have informed us that if the sending mailserver cannot immediately establish a connection to deliver the intended e-mail, the MTA should attempt to retry a connection to the EarthLink MX, rather than defaulting to the earthlink.net 'A' record. If, upon review of your mail, you believe that your report should be personally reviewed by an Abuse staff member, please reply to this message. Include this entire text and your original message located below. When resubmitting reports, please include a brief explanation as to why resubmission was necessary. When we receive your resubmission with this message included, we'll investigate the matter and use it to further refine our filters. Thanks for your report, EarthLink Abuse Staff To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
