How to connect telnet mail server ubuntu

To connect to a telnet mail server on Ubuntu, you can follow these steps:

Step 1: Install telnet

If you haven't already, install telnet on your Ubuntu system by running the following command:

sudo apt-get install telnet

Step 2: Open a terminal

Open a terminal on your Ubuntu system.

Step 3: Connect to the mail server

Use the telnet command to connect to the mail server. The syntax is:

telnet <mail_server_hostname> <port>

Replace <mail_server_hostname> with the hostname or IP address of the mail server, and <port> with the port number used by the mail server (usually 25 for SMTP).

For example:

telnet mail.example.com 25

Step 4: Authenticate (optional)

If the mail server requires authentication, you'll need to enter your username and password. You can do this by typing:

HELO <your_email_address>

Replace <your_email_address> with your email address. This will send a HELO (Hello) command to the mail server, which will prompt you to enter your username and password.

Step 5: Send a command

Once you're connected, you can send commands to the mail server using the telnet prompt. For example, you can send a MAIL FROM command to specify the sender's email address:

MAIL FROM:<your_email_address>

Replace <your_email_address> with the email address you want to use as the sender.

Step 6: Exit

When you're finished, you can exit the telnet session by typing:

quit

This will disconnect you from the mail server.

Example telnet session

Here's an example telnet session to connect to a mail server:

$ telnet mail.example.com 25
Trying 192.0.2.1...
Connected to mail.example.com.
Escape character is '^]'.
220 mail.example.com ESMTP Postfix
HELO example.com
250 mail.example.com
MAIL FROM:<[email protected]>
250 2.1.0 Ok
quit
221 2.0.0 Bye
Connection closed.

In this example, we connected to the mail server mail.example.com on port 25, sent a HELO command to authenticate, specified the sender's email address using the MAIL FROM command, and then exited the session using the quit command.