[TELNET] SMTP
=============

### Connect to the server

```
$ telnet <servername_or_ip> <port>
```

*(Default port : 25)*


### Polite people says Hello first

```
> EHLO <servername>
```

### Authentification

First encode username and password in B64:

```
$ perl -MMIME::Base64 -e 'print encode_base64("<username>");'
$ perl -MMIME::Base64 -e 'print encode_base64("password");'
```

Then inside the telnet

```
> AUTH LOGIN
```

The server return:

```
> 334 VXNlcm5hbWU;
```

***B64 encoded string asking for username***

Paste the base64 encoded username:

```
> dXNlcm5hbWU=
```

Then the server return:

```
> 334 UGFzc3dvcmQ6;
```

***B64 encoded string asking for password***

Paste the B64 encoded password:

```
> cGFzc3dvcmQ=
```

Now the server should return:

```
> 235 Authentication succeeded
```

### Define Sender

```
> MAIL FROM:<sender@domain.tld>
```

The server should return:

```
> 250 2.1.0 Ok
```

***Warning : Even if the sender is wrong or not authorized the server always return Ok, because the checking is done with both sender and recipient***

### Define Recipient

```
> RCPT TO:<recipient@domain.tld>
```

The server should return:

```
> 250 2.1.0 Ok
```

### Insert DATA

```
> DATA
```
The server return:

```
> 354 End data with <CR><LF>.<CR><LF>
```

Enter actual mail content:

```
> From: sender@example.com
> To: recipient@example.com
> Subject: Test message
> Reply-to: sender@example.com
> This is a test message.
```

Then press enter, a dot then enter again:

```
> 250 2.6.0 Queued mail for delivery
```

Disconnect

```
> QUIT
```

The server return :

```
> 221 <servername> ESMTP <serverbannner> closing connection
```