centos7 DKIM 설정

# cd /etc/opendkim/keys/
# mkdir mydomain.com
# opendkim-genkey -D /etc/opendkim/keys/mydomain.com -d mydomain.com -s selector
# ls -al /etc/opendkim/keys/mydomain.com


# vi /etc/opendkim/keys/mydomain.com/selector.txt 

selector._domainkey     IN      TXT     ( "v=DKIM1; k=rsa; "
          "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDFsK5zq3xYuxr7q10qc36LranoE8unpiP70zclaU1Bh7DiSdafMY3K3Jn3x9b2HNf+dpAJ5w4baII7cTdi8tyySxPn4Z8zqD7VHxDojiE4ACgi3yKCKwuhSJoi44D3oakPR/2Mkv+SRWJEezouPLp6OgzVvJ5FWuJAYZtNSWMWFwIDAQAB" )  ; ----- DKIM key selector for mydomain.com
이런식으로 넣기 
selector._domainkey.mydomain.com "v=DKIM1 k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDFsK5zq3xYuxr7q10qc36LranoE8unpiP70zclaU1Bh7DiSdafMY3K3Jn3x9b2HNf+dpAJ5w4baII7cTdi8tyySxPn4Z8zqD7VHxDojiE4ACgi3yKCKwuhSJoi44D3oakPR/2Mkv+SRWJEezouPLp6OgzVvJ5FWuJAYZtNSWMWFwIDAQAB"

# dig @8.8.8.8 selector._domainkey.mydomain.com txt



# vim /etc/opendkim.conf
AutoRestart             Yes
AutoRestartRate         10/1h
UMask                   002
Syslog                  yes
SyslogSuccess           Yes
LogWhy                  Yes
Canonicalization        relaxed/simple
ExternalIgnoreList      refile:/etc/opendkim/TrustedHosts
InternalHosts           refile:/etc/opendkim/TrustedHosts
KeyTable                refile:/etc/opendkim/KeyTable
SigningTable            refile:/etc/opendkim/SigningTable
Mode                    sv
PidFile                 /var/run/opendkim/opendkim.pid
SignatureAlgorithm      rsa-sha256
UserID                  opendkim:opendkim
Socket                  inet:8891@localhost

# vim /etc/opendkim/TrustedHosts
127.0.0.1
localhost
mydomain.com


#vim /etc/opendkim/KeyTable
selector._domainkey.mydomain.com mydomain.com:selector:/etc/opendkim/keys/mydomain.com/selector.private


# vim /etc/opendkim/SigningTable
*@mydomain.co.kr selector._domainkey.mydomain.com


# vim /etc/mail/sendmail.mc
::: 맨 하단에 추가 아래문구 추가.
INPUT_MAIL_FILTER(`opendkim',`S=inet:8891@localhost')dnl
::: 저장종료

# cd /etc/mail/
# m4 sendmail.mc > sendmail.cf


# systemctl restsart opendkim
# systemctl enable opendkim