How to install pop3 in sendmail linux mail server

To install POP3 (Post Office Protocol version 3) on a Sendmail Linux mail server, you'll need to follow these steps:

Step 1: Install the required packages

You'll need to install the sendmail and pop3d packages. The exact package names may vary depending on your Linux distribution. Here are some common package names:

You can install the packages using the package manager of your Linux distribution. For example, on RHEL/CentOS/Fedora:

sudo yum install sendmail pop3d

On Ubuntu/Debian:

sudo apt-get install sendmail pop3d

On openSUSE:

sudo zypper install sendmail pop3d

Step 2: Configure Sendmail

Edit the Sendmail configuration file /etc/sendmail.cf (or /etc/mail/sendmail.cf on some systems) using a text editor:

sudo nano /etc/sendmail.cf

Add the following lines at the end of the file:

Dpop3dPath /usr/sbin/pop3d
Dpop3dArgs -l /var/log/pop3d.log

These lines tell Sendmail to use the pop3d daemon and specify the log file location.

Step 3: Configure the POP3 server

Create a new file /etc/pop3d.conf (or /etc/mail/pop3d.conf on some systems) using a text editor:

sudo nano /etc/pop3d.conf

Add the following lines to the file:

AuthType default
AuthInfoMethod login
ListenAddress 127.0.0.1
Port 110

These lines configure the POP3 server to listen on localhost (127.0.0.1) on port 110.

Step 4: Restart Sendmail and POP3

Restart the Sendmail and POP3 services to apply the changes:

sudo service sendmail restart
sudo service pop3d restart

Step 5: Test the POP3 server

Use a POP3 client (such as telnet or a mail client like Thunderbird) to test the POP3 server:

telnet localhost 110

You should see a response from the POP3 server. You can then login using your email username and password to retrieve your email.

That's it! You should now have a working POP3 server on your Sendmail Linux mail server.