+ cat >/etc/dovecot/conf.d/20-lmtp.conf <<EOF
+protocol lmtp {
+#per https://wiki2.dovecot.org/Pigeonhole/Sieve/Configuration
+ mail_plugins = \$mail_plugins sieve
+# default was
+ #mail_plugins = \$mail_plugins
+
+# For a normal setup with exim, we need something like this, which
+# removes the domain part
+# auth_username_format = %Ln
+#
+# or else # Exim says something like
+# "LMTP error after RCPT ... 550 ... User doesn't exist someuser@somedomain"
+# Dovecot verbose log says something like
+# "auth-worker(9048): passwd(someuser@somedomain): unknown user"
+# reference: http://wiki.dovecot.org/LMTP/Exim
+#
+# However, I use this to direct all mail to the same inbox.
+# A normal way to do this, which I did at first is to have
+# a router in exim almost at the end, eg 950,
+#local_catchall:
+# debug_print = "R: catchall for \$local_part@\$domain"
+# driver = redirect
+# domains = +local_domains
+# data = $u
+# based on
+# http://blog.alteholz.eu/2015/04/exim4-and-catchall-email-address/
+# with superflous options removed.
+# However, this causes the envelope to be rewritten,
+# which makes filtering into mailboxes a little less robust or more complicated,
+# so I've done it this way instead. it also requires
+# modifying the local router in exim.
+ auth_username_format = $u
+}