On 2017.08.25. 18:20, Viktor Dukhovni wrote: > > Yes, but ... > >> relay_transport = smtp:backend > > On MX gateway hosts that receive inbound mail, use "relay:..." not > "smtp:..." for your relay transport, and let outbound mail from > your system use "smtp". This reduces contention between inbound > and outbound traffic, in particular slow outbound mail will not > delay inbound mail. > >> relay_domains = mydomain.com >> sender_dependent_relayhost_maps = >> inline:{prioritysender.com=smtpfast:backend } > > No, because sender_dependent_relayhost_maps (unsurprisingly) only > changes the relayhost, not the transport. If your priority is by > origin, and not by destination, you may have to use three Postfix > instances, with low priority traffic shunted to the default slow > instance, and high priority traffic to the fast instance, with the > front end instance acting as a switch to separate the two flows. > > Ultimately Postfix transport selection and concurrency limits are > (correctly) destination based, so to implement sender-dependent > behaviour you need to split the flow by sender, which can only be > done by handling off to another MTA (instance) with sender-dependent > relay settings. > > You could use: > > > http://www.postfix.org/postconf.5.html#sender_dependent_default_transport_maps > > but only when the destination domain is not a "relay" domain or > similar, that is, only if mail for the destination in questin just > goes whereever the MX records point with no transport overrides > beyond (sender_dependent_default_transport_maps) which selects a > sender dependent *default* transport. >
I'm using permit_auth_destination and it does not play without relay_domains. well, looks like I found few solutions: 1. change transport using FILTER via check_sender_access in smtpd_sender_restrictions - fine until there is no other filter action 2. alter nexthop with sender_dependent_relayhost_maps - require additional address on the backend As I understand concurrency limits will differ from ones on default route in both cases. IMO it may be useful to allow alter transport in sender_dependent_relayhost_maps as well in future releases of postfix