[exim] Enforce TLS for outgoing mails

Hello,

I'm sorry if this is a newbie question. I'm trying to enforce TLS for all outgoing 
messages, my first attempt was to add to acl_check_rcpt:
   deny    message       = TLS is required
           domains       = +local_domains
           condition     = ${if eq{$tls_cipher}{}{yes}{no}}

However this filtered out all incoming messages as well. My second attempt was to modify
the dnslookup router, because all outgoing messages go through it. Here's how it looks
like now:

dnslookup:
driver = dnslookup
domains = ! +local_domains
transport = remote_smtp
condition = "${if eq{$tls_cipher}{}{yes}{no}}"
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more

Despite this setting I'm still allowed to send mail without using TLS. What am I doing
wrong? Any help appreciated.

--
Regards,

Patryk Rzadzinski