Priority of MX record

[²z©÷]

※ 引述《barmar at alum.mit.edu (Barry Margolin)》之銘言：
> In article <dohgnf$vqt$1 at sf1.isc.org>,
>  leicheong.bbs at bbs.sayya.org (理昌) wrote:
> > Hello,
> >     Say we have a domain name of abc.com. The DNS entries are as
> > the following.
> > abc.com MX 10 mail.abc.com
> > abc.com MX 20 mail2.abc.com
> >     This morning, we find that our internet connection of mail.abc.com
> > is not working. But while mail2.abc.com works normally, it seems we're
> > still not getting any emails. So finally I have to switch the priority
> > of them to make it work.
> > Aren't the "priority" of a MX record be used as a fallback when one
> > mail host is inaccessable? Or do I have some misunderstanding on this
> > matter?
> Your understanding is correct.  Are you sure that mail2 is set up
> properly to deliver the mail?  If it's trying to connect to mail via its
> Internet connection rather than an alternate path, the mail will still
> be stuck on mail2.
I think it should be. Because I just exchange the priority values
of the two MX records to make it work. That means the settings should
be correct.

Really strange.

P.S.: The network problem is cased by a malfunctioned CISCO swtich in
in the building... Could it be that the nearest router somehow can't
deliver "Destination not reachable" RIP signal so the fallback fails?
(I've not tried the response from outside, so this is juat a guess)
--
※ Origin: SayYA 資訊站 <bbs.sayya.org> 
◆ From: ip-84-126-134-202.rev.dyxnet.com