sed -i 's%O SmtpGreetingMessage=$j Sendmail $v/$Z; $b%O SmtpGreetingMessage=$j; $b%g' /etc/mail/sendmail.cf

-​수정 전

ioniere@ioniere-KVM:~$ telnet xxx.xxx.xxx.51 25
Trying xxx.xxx.xxx.51...
Connected to xxx.xxx.xxx.51.
Escape character is '^]'.
220 mail.yeonghoon.kim ESMTP Sendmail 8.15.2/8.15.2; Thu, 14 Nov 2019 10:51:55 +0900

-수정 후

ioniere@ioniere-KVM:~$ telnet xxx.xxx.xxx.51 25
Trying xxx.xxx.xxx.51...
Connected to xxx.xxx.xxx.51.
Escape character is '^]'.
220 mail.yeonghoon.kim ESMTP Sendmail; Thu, 14 Nov 2019 14:35:48 +0900