Sendmail Configuration

Question : How to configure sendmail in Linux rhel 6 centos 6 ? 

Question : Step by Step Sendmail configuration in centos 6 ? 

IP - 10.20.2.33 

Hostname - khandwa.lokesh.com

OS - CentOS 6

MTA - Mail Transfer Agent

SMTP - Simple mail transfer protocol

Port : SMTP -25 | POP: 110 | POPs: 995 | IMAP: 143 | IMAPs: 993

Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.

To install sendmail

# yum install sendmail*

Configure Sendmail file

# vi /etc/mail/sendmail.mc

Serarch line  : DEMON_OPTIONS & disable by adding " dnl"

Output after disable

Search LOCAL_DOMAIN & change according your domain

Save & Exit

Now we will divert sendmail.mc file in sendmail.cf  , it is always configured

#  M4  /etc/mail/sendmail.mc  >  /etc/mail/sendmail.cf

Sendmail by default deny for everyone so we set permission

# vi  /etc/mail/access

We can add network/IP/ Hostnam for network  10.20.2.0,we not add zero bits in this file

Edit the file named  "/etc/mail/local-host-names" and add the following ( machine ip address for example my ip is 10.20.2.33)

# vi  /etc/mail/local-host-names

Now restart sendmail

#  service  sendmail  restart

# chkconfig  sendmail  on

Add user for mail

# useradd -s /sbin/nologin user1

Set Password for user

# passwd user1

# useradd -s /sbin/nologin user2

# passwd user2

# useradd -s /sbin/nologin user3

# passwd user3

Test the mail server

# telnet khandwa.lokesh.com

Quit for exit..

1.Send mail to user

# mail -v user1@lokesh.com

Or

# mail -v user1@10.20.2.33

Subject:  type subject & enter

Hello

This is a test message
. Here dot (.) exit message and send

If we want user " user1" get all mails in " Sales" Group. So we will set aliases

To set aliases

# vi /etc/aliases