[Dovecot] Proxying LMTP - Auth PASS lookup failed

[Edward Carraro]

Working now...

I enabled port 24 in dovecot on both proxy and backend (previously i was
just telling postfix to listen to port 24 on the backend server) --
Confirmed lmtp on 24 was working on both servers by telnet localhost 24 (220
Dovecot LMTP ready response)

here are my settings

proxy is using inet for LMTP

dovecot/conf/10-master.conf
service lmtp {
  unix_listener lmtp {
    #mode = 0666
  }

  # Create inet listener only if you can't use the above UNIX socket
  inet_listener lmtp {
    port = 24
  }
}

postfix/main.cf

virtual_transport = lmtp:localhost
mailbox_transport = lmtp:localhost

----

backend is also inet (to receive) and unix socket (to deliver locally)

dovecot/conf/10-master.conf
service lmtp {
  unix_listener lmtp {
    #mode = 0666
  }

  unix_listener /var/spool/postfix/private/dovecot-lmtp {
   group = postfix
#   mode = 0660
   user = postfix
  }

  # Create inet listener only if you can't use the above UNIX socket
  inet_listener lmtp {
    port = 24
  }
}

postfix/main.cf
virtual_transport = lmtp:unix:private/dovecot-lmtp
mailbox_transport = lmtp:unix:private/dovecot-lmtp

postfix/master.cf
removed: 24       inet  n       -       n       -       -       lmtp