[Exim] mx domains

How to correct deliver mails. Because my sever deliver mails for non MX
servers :(.

I have in config:
relay_to_domains = domain.net : *.domain.net
....
other_port_relay:
driver = dnslookup
domains = ! +local_domains : +relay_to_domains
transport = relay_over_smtp_port
ignore_target_hosts = 127.0.0.0/8
headers_add = X-added-header: added by $primary_hostname\n


I think what this not good.