With config
relay_recipient_maps =
address_verify_map = ${dbtype}:${datadir}/verify_cache
address_verify_transport_maps =
static:relay-remote:[internal.DDDD.com]:25
relay_transport = relay-remote:[internal.DDDD.com]:10587
remote recipient verification, and subsequent relay, works as expected.
Testing option (2) above, I now periodically rsync
/etc/postfix/valid_email_addresses.lmdb
which contains a generated list of valid users & aliases on the backend, from
the backend to my frontend.
I'm clear on how to use the local .lmdb _instead_ of remote verification.
Is it possible to use it as a backup/fallback to remote verification? I.e., if
remote verification FAILs, additionally check the .lmdb for a match, deferring
only if there's a FAIL there as well?
If possible, the goal here is to use the faster persistent valid-address DB
that Postfix is managing anyway, and only refer to the lmdb if there's a FAIL.
Reading
http://www.postfix.org/postconf.5.html#relay_recipient_maps
IIUC, it's either/or. Either = (empty), and uses recipient verification, or =
(table), which triggers the lookup.
