[sendmail]when cannot connection from remort host and cannot send mail

• 원격에서 sendmail 접속 안될때
• reason : For security reason sendmail is by default configured to accept connection from local system (127.0.0.1). This should avoid open mail relay problem.

• solution :

# vi /etc/mail/sendmail.mc

• find following sentence 

                         DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl

• and comment or remove above line and insert new line that read as follows:

                         DAEMON_OPTIONS(`Port=smtp,Name=MTA')dnl

• Above line will force to accept connection from any host. Save the file. Regenerate sendmail configuration file using m4:

# m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
# /etc/init.d/sendmail restart

• 그런데 이때 다음과 같은 에러가 발생 할 수 도 있다.
  -m4: m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf /etc/mail/sendmail.mc:10: m4: Cannot open /usr/share/sendmail-cf/m4/cf.m4:
• solution : This errors simply means you do not have the sendmail-cf package installed. 암튼 위 패키지를 설치하면 된다

• 다 하고 났는데 이제는 클라이언트에서 메일 접속하고 발생할 때 access deny가 나온다.
• solution : 
• 그래도 안되면 다음파일열어서 전부 주석처리
• vi /etc/mail/local-host-names

1) access파일 열어서 아이피 추가

# vi /etc/mail/access

# Check the /usr/share/doc/sendmail/README.cf file for a description
# of the format of this file. (search for access_db in that file)
# The /usr/share/doc/sendmail/README.cf is part of the sendmail-doc
# package.
#
# If you want to use AuthInfo with "M:PLAIN LOGIN", make sure to have the
# cyrus-sasl-plain package installed.
#
# By default we allow relaying from localhost...
Connect:localhost.localdomain           RELAY
Connect:localhost                       RELAY
Connect:127.0.0.1                       RELAY
Connect:999.99.99.99                  RELAY   <- 이런식으로 아이피 추가

2)

# /usr/sbin/makemap hash /etc/mail/access < /etc/mail/access