> On 8 Jan 2020, at 17:04, Wietse Venema <wie...@porcupine.org> wrote: > > Viktor Dukhovni: >> On Wed, Jan 08, 2020 at 09:36:48AM +0100, Thierry Fournier wrote: >> >>>> - An "smtp_nexthop_override_maps" feature that replaces the domain >>>> in the delivery request with one or more domain names. You decide >>>> the order of names in the result, and if the original domain >>>> should be part of the result. Specify [name], [name] to get >>>> comparable control as with your synthetic MX records. >>> >>> I like this idea, but it add a little bit of complexity for >>> understanding configuration. >> >> Which can also easily be done in your DNS resolver, including specifying >> equal >> weight or strictly ordered preferences. >> >>>> - Or, add support for multiple next-hop destinations in "relayhost", >>>> "transport_maps", and "default_transport". This changes the syntax >>>> and semantics of existing Postfix features. Again, specify [name], >>>> [name] to get comparable control as with your synthetic MX records. >>> >>> I like this idea. >> >> I am not convinced this is warranted. > > I am leaning towards usability, i.e. allow multiple nexthops in > transport maps, relayhost, and default_transport. It is the more > natural way to express these things than doing stuff in DNS > or introducing yet another configuration mechanism.
I agree. In other way the maintenance of a dedicated DNS server is not costless: it introduce a new cause of break, so it requires high availability, supervision and administration. Thierry > As for purity, the reason I stuck with single nexthops was scheduler > fairness, but that has never worked for multiple domains that resolve > to the same MX hosts. > > If we must implement true fairness we must change the qmgr/delivery > agent interface, and I estimate that having multiple nexthops would > not fundamentally make a difference. > > Wietse
