* Ronald Wiplinger (ronald@elmit.com) [011125 19:18]:
MX 0 mail.abc.com MX 10 mail-backup.abc.com MX 20 mail-backup.otherside.com
It would mean, that the mails will come to mail.abc.com, except the server is down (or even overloaded), If so, the next mail server would be used: mail-backup.abc.com, of if the entire site has a problem the mail-backup.otherside.com
In general, something sort of like that will happen. But MTA's aren't currently required to this by RFC although I don't know of one that doesn't (I'm not counting silly clients that have built-in MTAs...who know what they do). For example, qmail (which we use for these mailing lists) is much less agressive about trying secondary MXs than, say, sendmail.
And there they are !!!! and there they stay !!!! However, the normal user is not checking mail-backup.abc.com or mail-backup.otherside.com Actually, I not even want that the mails on these machines would be sort in into mailboxes for the users, ... it should be just here in a queue to delivery to mail.abc.com as soon as possible.
Ah, I think I see. Either you've given mail.abc.com and mail-backup.abc.com the same MX record or you've misconfigured the MTA on mail-backup.abc.com so that it thinks mail destined for mail.abc.com is also destined for itself. You don't say what the MTAs in question are but if it's sendmail, postfix, or qmail you'll probably want to have a look at the docs (for sendmail it's the "Bat" book from O'reilly, qmail www.qmail.org, and postfix www.postfix.org). You'll need to resend all of that mail from mail-backup.abc.com back to mail.abc.com though...something like formail -s sendmail foo@mail.abc.com < foo.mbox will work for mboxes. -- -ckm