+CHECK_DATA_LOCAL_ACL_FILE = /etc/exim4/data_local_acl
+
+# debian exim config added this in 2016 or so?
+# it's part of the smtp spec, to limit lines to 998 chars
+# but a fair amount of legit mail does not adhere to it. I don't think
+# this should be default, like it says in
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=828801
+# todo: the bug for introducing this was about headers, but
+# the fix maybe is for all lines? one says gmail rejects, the
+# other says gmail does not reject. figure out and open a new bug.
+IGNORE_SMTP_LINE_LENGTH_LIMIT = true
+
+# most of the ones that gmail seems to use.
+# Exim has horrible default of signing unincluded
+# list- headers since they got mentioned in an
+# rfc, but this messes up mailing lists, like gnu/debian which want to
+# keep your dkim signature intact but add list- headers.
+DKIM_SIGN_HEADERS = mime-version:in-reply-to:references:from:date:subject:to
+
+# recommended if dns is expected to work
+CHECK_RCPT_VERIFY_SENDER = true
+# seems like a good idea
+CHECK_DATA_VERIFY_HEADER_SENDER = true
+CHECK_RCPT_SPF = true
+CHECK_RCPT_REVERSE_DNS = true
+CHECK_MAIL_HELO_ISSUED = true
+
+MAIN_LOG_SELECTOR = +all
+
+# testing dmarc
+#dmarc_tld_file = /etc/public_suffix_list.dat
+EOF
+
+ f=/etc/cron.daily/refresh-dmarc-tld-file
+ cat >$f <<'EOF'
+#!/bin/bash
+cd /etc
+wget -nv -N https://publicsuffix.org/list/public_suffix_list.dat
+EOF
+ chmod 755 $f
+
+
+ ####### begin dovecot setup ########
+ # based on a little google and package search, just the dovecot
+ # packages we need instead of dovecot-common.
+ #
+ # dovecot-lmtpd is for exim to deliver to dovecot instead of maildir
+ # directly. The reason to do this is to use dovecot\'s sieve, which
+ # has extensions that allow it to be almost equivalent to exim\'s
+ # filter capabilities, some ways probably better, some worse, and
+ # sieve has the benefit of being supported in postfix and
+ # proprietary/weird environments, so there is more examples on the
+ # internet. I was torn about whether to do this or not, meh.
+ pi dovecot-core dovecot-imapd dovecot-sieve dovecot-lmtpd
+
+ # if we changed 90-sieve.conf and removed the active part of the
+ # sieve option, we wouldn\'t need this, but I\'d rather not modify a
+ # default config if not needed. This won\'t work as a symlink in /a/c
+ # unfortunately.
+ sudo -u $u /a/exe/lnf -T sieve/main.sieve $(eval echo ~$u)/.dovecot.sieve
+
+ # we set this later in local.conf
+ sed -ri -f - /etc/dovecot/conf.d/10-mail.conf <<'EOF'
+/^\s*mail_location\s*=/d