What does this line refer to dc_other_hostnames='vm25.local.lan' In /etc/exim4/update-exim4.conf.conf It contains my hosts name but it calls it other_hostnames.. somewhat confusing. Grepping for some documentation about that line gets no hits. grep -rl dc_other_hostname /usr/share/doc/exim* /usr/share/exim* Nothing either place.