From: CT on
My relay sends as follows:

90% - relayhost
10% - other hosts in transport (these go "directly" out)

This works well.

my question:
When the primary relayhost is "unavailable" what would be
the best way to *send* the 90% out.. ?
(not about load balancing)


Thx
Charles

From: Noel Jones on
On 4/19/2010 9:34 AM, CT wrote:
> My relay sends as follows:
>
> 90% - relayhost
> 10% - other hosts in transport (these go "directly" out)
>
> This works well.
>
> my question:
> When the primary relayhost is "unavailable" what would be
> the best way to *send* the 90% out.. ?
> (not about load balancing)
>

If your public IP is suitable for a mail server (static IP,
non-generic rDNS hostname, rDNS hostname points back to your
IP), then the easiest thing is to deliver mail directly
without using the relayhost. In this case, one could argue
that you shouldn't be using the relayhost in the first place.
I believe switching from using a relayhost to not requires a
configuration change and can't fall over automatically.

If you must use a relayhost, then you can define an alternate
relayhost in smtp_fallback_relay OR use private MX records to
define where relayhost mail should go to.
http://www.postfix.org/postconf.5.html#smtp_fallback_relay

-- Noel Jones