Re: [exim] secondary MX: allow only a set of users

On Thu, 20 Dec 2007, Wouter Verhelst wrote:
> On Thu, Dec 20, 2007 at 09:50:01AM +0100, Leonardo Boselli wrote:
> > Il 19 Dec 2007 alle 22:11 Daniel Collis-Puro immise in rete
> > > Why not use a recipient verification callout for the destination mail
> > > server? Something like:
> > NOT feasible:
> Sure it is.
> > the secondary mx is usually used when the primary is of, or overloaded
> > and do not accept more connections or give immediately a 421 error.
> Look for 'smtp_reserve_hosts'. With this, you can allow the backup MX to
> connect to the master even when the master is already 4xx'ing other
> hosts because of things like smtp_load_reserve.
> > Also for other reason caching, unless on a file that can be
> > easily moved between the MX 13 and MX 20, is not usable. --
> Care to give a bit more info on that?

I expect that for some weeks will be some "erratic" maintenace periods
when one or more of the server will be off or just unreacheable.
so i cannot consider any solution that cannaot be carried across reboot or
requires the availability of the main server.