On Jul 25, 2008, at 7:35 AM, [EMAIL PROTECTED] wrote: > Here is the setup: > mx1.xxxx.com priority 10 > mx2.xxxx.com priority 20 > > As I understand it, sendmail will try to use mx2.xxxx.com if > mx1.xxxx.com is down? Well, but sendmail just put the mail in queue > and tried mx1.xxxx.com later. > Have I misunderstood the mechanism or what have I done wrong? > Thanks. >
If the first server answers, but returns an error during the SMTP session, most sending MTAs will treat that as a failed delivery attempt and queue the message to try later. If the first server sends a TCP RST or the connection times-out, most MTAs will try the next listed MX record. It's nothing to do with DNS, it's just MTA behavior. Brian Keefer Sr. Systems Engineer www.Proofpoint.com "Defend email. Protect data."
