sendmail is a mail transfer agent (MTA) used to send emails between computer systems by using simple mail transfer protocol (SMTP) . Sendmail project can be accessed from <a href="http://www.sendmail.org">www.sendmail.org</a>
sendmail
<h1>Install On Ubuntu, Debian, Mint, Kali</h1> tool is provided by different packages on Ubuntu, Debian,Mint, Kali or
debbased distributions. In this case, we will install the package named
postfix.
rpm
<pre class="">$ sudo apt install postfix</pre>
<h1>Install On Fedora, CentOS, RedHat</h1>
Inbased distributions likeFedora, CentOS, RedHat we will use
postfixpackage to install
sendmailtool.
sendmail
<pre class="">$ sudo yum install postfix</pre>
<h1>sendmail.cf Configuration File</h1>command has different configuration options. We can provide these options interactive command line during
sendmailcommand execution. But we can also set these options in configuration file
/etc/sendmail.cfpermanently for all usages.
sendmail
<h1>Sendmail Local Users</h1>command can send mail to the local users. We just need to supply the user name of the local user to the sendmail utility. Then we will provide the mail content in a text or ASCII formation. For example we will set the subject with the
Subject:` line like below.
$ sendmail ismail
List Mails or Inbox
Linux distributions provide the mail
command which is used to list emails or inbox of the users. We can use mail
command without providing an option to list currently logged user inbox or mails. We will see that previously sent mail will be listed and displayed in detail.

We can see that detailed information about the email is listed.
- Date
- Return Path
- Delivered To
- Received
- Subject
- Message ID
Sendmail To The Internet
We can also send email to the internet user or popular email providers. We will just provide the email address of the user. Keep in mind that the smtp configuration should be done properly in order to send email to the internet. In this case we will send email to the poftut@gmail.com
$ sendmail poftut@gmail.com
