Configure Email from Linux Machine

 

Linux Version: Oracle Linux 6.7

Sendemail  : smtp.gmail.com

Hostname : srv1 

1) Install the rpm : sendmail, mailutils, sendmail-cf

yum install sendmail -y

yum install mailutils -y

yum install sendmail-cf -y

* To check the directory mail under /etc and the files are created.

[root@srv1]# ls -l /etc/mail 

total 192
-rw-r--r--. 1 root root   469 Jul 12  2016 access
-rw-r-----. 1 root root 12288 Sep 15 13:18 access.db
-rw-r--r--. 1 root root     0 Sep 15 13:18 aliasesdb-stamp
-rw-r--r--. 1 root root   233 Jul 12  2016 domaintable
-rw-r-----. 1 root root 12288 Sep 15 13:18 domaintable.db
-rw-r--r--. 1 root root  5584 Jul 12  2016 helpfile
-rw-r--r--. 1 root root    64 Jul 12  2016 local-host-names
-rw-r--r--. 1 root root   997 Jul 12  2016 mailertable
-rw-r-----. 1 root root 12288 Sep 15 13:18 mailertable.db
-rwxr-xr-x. 1 root root  2700 Jul 12  2016 make
-rw-r--r--. 1 root root    92 Jul 12  2016 Makefile
-rw-r--r--. 1 root root 58439 Jul 12  2016 sendmail.cf
-rw-r--r--. 1 root root  7202 Jul 12  2016 sendmail.mc
-rw-r--r--. 1 root root 41521 Jul 12  2016 submit.cf
-rw-r--r--. 1 root root   941 Jul 12  2016 submit.mc
-rw-r--r--. 1 root root   127 Jul 12  2016 trusted-users
-rw-r--r--. 1 root root  1847 Jul 12  2016 virtusertable
-rw-r-----. 1 root root 12288 Sep 15 13:18 virtusertable.db

2) Backup the sendmail configuration files

[root@srv1 etc]# cd /etc/mail
[root@srv1 mail]# cp sendmail.cf sendmail.cf.orig
[root@srv1 mail]# cp sendmail.mc sendmail.mc.orig

3) Configure SMTP Authentication 

[root@srv1 mail]#  mkdir -m 700 -p /etc/mail/auth
[root@srv1 mail]# vi /etc/mail/auth/auth-info    

Copy the entries as follow (Replace username and password)

AuthInfo:smtp.gmail.com "U:root" "I:<USERNAME>@gmail.com" "P:<PASSWORD>"

 * Save the file and make database-map: 

[root@srv1 auth]# makemap hash auth-info < auth-info
[root@srv1 auth]# ls -lrt                                                    #See the files are generated
total 12
-rw-r--r--. 1 root root    84 Sep 15 13:25 auth-info
-rw-r-----. 1 root root 12288 Sep 15 13:25 auth-info.db

4) Configure sendmail.mc

vi /etc/mail/sendmail.mc

Copy the following lines before first MAILER in the file 

* Replace the highlighted according to your email server

define(`SMART_HOST',`smtp.gmail.com')dnl
define(`RELAY_MAILER_ARGS', `TCP $h 587')dnl
define(`ESMTP_MAILER_ARGS', `TCP $h 587')dnl
define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
FEATURE(`authinfo',`hash /etc/mail/auth/auth-info')dnl
TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')

* Save the file and exit;

* Make the sendmail.cf:

 [root@srv1 mail]# m4 sendmail.mc > sendmail.cf

5) Start sendmail service 

[root@srv1 mail]# sh /etc/rc.d/init.d/sendmail start
Starting sendmail:                                         [  OK  ]
Starting sm-client:                                        [  OK  ]

6) Test if the mail is working.
[root@srv1 mail]# echo 'test email from me'| mail -s TEST Email sample@gmail.com