>From: "CLIFFORD ILKAY" <[EMAIL PROTECTED]>
> The ISP should be substantially more reliable. A twist on what you are
> suggesting Les is to have the ISP be the secondary MX and set up the MTA at
> the ISP relay for austethical.com.au. Set the SME 5 server at the office to
> be the primary MX. If the primary goes down for whatever reason, network
> problems, hardware failures, software upgrades or problems, mail for
> austethical.com.au would not be bounced because it would end up at the
> ISP's mail server. The secondary at the ISP would accumulate the mail and
> keep trying to relay it to the primary. When the primary comes up, the
> secondary will relay all the mail that has accumulated to the primary and
> the users will not lose any mail.
Well, my machines are as reliable as my ISPs. In fact several ISPs have gone
out of business and my machines are still chugging away... Having a
secondary MX is not as critical as having a secondary DNS server at
a different location. Almost all mail destined for your server is going
to be sent through some other relay anyway (i.e. the sender's server)
and that relay will keep trying to deliver to you just the same as a designated
secondary MX. However, if your DNS server is unreachable the sending
relay will bounce the message instead of queuing and retrying. It might
be an advantage to have the secondary MX server if it understands ETRN
and you send it one as soon as you come back on line to have the queued
mail delivered immediately - otherwise it may take a while before the
queue runs happen.
Les Mikesell
[EMAIL PROTECTED]
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