==== Exim4 Smart Host + Relay Local Network Hosts ====
직접 수정하거나 ''dpkg-reconfig exim4-config''로 해도 됩니다.
<codeprism hl=4,5,6,10,11>
# /etc/exim4/update-exim4.conf.conf
# This is a Debian specific file

dc_eximconfig_configtype='smarthost'
dc_other_hostnames='localhost;gamu.kr'
dc_local_interfaces='127.0.0.1 ; ::1 ; 192.168.0.40'
dc_readhost=''
dc_relay_domains=''
dc_minimaldns='false'
dc_relay_nets='192.168.0.0/24' 
dc_smarthost='smtp-relay.brevo.com::587:smtp.gmail.com::587'
CFILEMODE='644'
dc_use_split_config='false'
dc_hide_mailname='false'
dc_mailname_in_oh='true'
dc_localdelivery='mail_spool'
</codeprism>
설정후에는 
<codeprism lang=bash>
sudo update-exim4.conf
sudo systemctl restart exim4
</codeprism>
메일을 보낼 호스트에서 
<codeprism cmdout=2-10 user=baeky host=bigboss>
$ telnet n40l 25
Trying 192.168.0.40...
Connected to n40l.
Escape character is '^]'.
220 localhost ESMTP Exim 4.98.2 Wed, 04 Feb 2026 23:56:23 +0900
</codeprism>
''telnet'' 종료는 <Ctrl>+<]>, ''quit''

다른 호스트에서 간편하게 메일서버의 릴레이 기능을 이용하려면 [[linuxfromscratch/rangeoverpackages/msmtp-1.8.32|msmtp-1.8.32]] 사용을 고려해보세요.