how droplets ssh clients generally authenticate ? 1- using passwords (which are less secure and not recommended) 
2- SSH keys (which are very secure and strongly recommended)
what information do you need To log in to your Droplet with SSH?  The Droplet’s IP address: 

The default username on the server:
The default username is root on most operating systems, like Ubuntu and CentOS. Exceptions to this include Rancher, where you’ll log in as rancher, and FreeBSD, where you’ll log in as freebsd
The default password for that username, if you aren’t using SSH keys:
If you uploaded SSH keys to your account and chose Add SSH Keys upon Droplet creation, you can connect to the Droplet using your preferred SSH client or command line. If you did not use the SSH option, the Droplet’s password is the password you set during creation what are the different options that a droplet can has?  
what is “container distribution” image? A container distribution is basically a Linux distribution built and optimized for using Docker containers
what kind of droplets are good for website hostings? Basic Droplets
what kind of droplets are good for:
• batch processing large data sets
• large builds
• video encoding
CPU-Optimized Performance Droplets
what kind of droplets are good for:
• high-performance SQL or NoSQL databases
• large in-memory caches and indexes
• real-time big data processing
• applications with large JVM requirements
Memory-Optimized Performance Droplets
what kind of droplets are good for:
• large NoSQL databases (like MongoDB and Elasticsearch)
• time series databases
• other data warehouses
Storage-Optimized
what is VPC? A Virtual Private Cloud (VPC) is a private network interface for collections of DigitalOcean resources. VPC networks provide a more secure connection between resources because the network is inaccessible from the public internet and other VPC networks. Traffic within a VPC network doesn’t count against bandwidth usage.
how can you run in to your droplet? SSH keys, which provide more security than a password.
Password, which allows you to create your own password for the new Droplet.
what is PTR record ? A PTR (pointer) record, also known as an rDNS (reverse DNS) record, maps a domain name to an IP address.
how to set a PTR record for your droplet ? in otherwords how to assign a domain to your droplet? We automatically create PTR records for Droplets based on the name you give that Droplet in the control panel. The name must be a valid FQDN, so using example.com as the Droplet name will create a PTR record, but ubuntu-s-4vcpu-8gb-fra1-01 or my-droplet will not. Droplets with IPv6 enabled will only have PTR records enabled for the first IPv6 address assigned to it, not to all 16 addresses available.
How to Connect to your Droplet via OpenSSH? 1- ssh root@203.0.113.0 or ssh -i /path/to/private/key username@203.0.113.0 if you have several keys
how to connect to your Droplet via putty?

Configuring PuTTY

1- fill IP
fill in the field labeled Host Name (or IP Address) with your Droplet’s IP address

2- choose SSH version
Next, click on SSH in the left sidebar (under Connection). Make sure 2 is selected for SSH protocol version

3- specify an SSH key if needed
Specify an SSH Key If Needed
If you will use a username and password to connect to your Droplet, skip this step.
If you previously created an SSH key pair, uploaded the public key to your account, and specified the key when you created the Droplet, open the Auth subcategory.
In the Private key file for authentication section, click the Browse button.
then:
Search for the private key file, which ends in .ppk, and click Open in the file window.

4- enter your server’s username
Next, in the Connection subheading in the Data configuration section, enter your server’s username in the Auto-login username field. For the initial setup, this should be the root user, which is the administrative user of your server. If you’re using Rancher, or FreeBSD, the username is corerancher, or freebsd instead of root, respectively.

6- save a session for your setting
Finally, you can save these preferences to avoid typing them manually in the future. Click on Session in the left sidebar, then add a name in the text box under Saved Sessions and click Save on the right.

Connecting

1- return to the Session screen
2- select the session you would like to use in the Saved Sessions section
3- click Load to recall the settings. This auto-fills all of the fields with the values you initially selected
4- click the Open button to connect to your Droplet

what is droplet console?

The Droplet Console is a browser-based way to connect to Droplets. Instead of using ssh in a local terminal, you can use the Droplet Console in your preferred web browser.
It also provides one-click SSH access to your Droplet without the need for a password or manual SSH key configuration.

what are droplet console limitations and notes? • The Droplet Console does not yet support FreeBSD
• Port 22 is the default port for SSH, so you don’t need to change anything unless you’ve previously modified your sshd configuration
• Your cloud firewall or host firewall must accept SSH traffic on port 22
how to connect to your droplet via droplet console? 1- the Droplet must have the Droplet agent installed (The agent is installed by default on all new Droplets created after August 2021)
2- In the Droplet Console section, enter the user you want to log in as in the Log in as… field. By default, this is set to root
what is the most recomended protocol for transfering filese from your local computer to droplet? using SFTP (SSH File Transfer Protocol) with FileZilla
what are the tools for transfering file via sftp via command line? rsync & OpenSSH’s sftp and scp
how to transfer files using fileZilla?

1- Open FileZilla and then click Settings in the Edit drop-down menu.
2- In the Connection section, click SFTP. This is where you add your Droplet’s private SSH key.
3- Click Add key file…, then locate your Droplet’s private SSH key on your local machine
4- If FileZilla prompts you to convert the file into a supported format, click Yes
5- After you add the SSH key, open the File drop-down menu and click Site Manager.
6- Click New Site and enter the name of the Droplet
7- In the protocol field, select SFTP from the drop-down menu
8- 

  • Host: The IP address of your Droplet.
  • Port: Enter the port you use to connect to the Droplet (port 22 is the default).
  • Logon Type: Select Interactive.
  • User: Enter the username you are connecting to the Droplet with (root is the default user on most Droplets).

9- Once you have entered your settings, click Connect.

Note: If you receive the error Disconnected: No supported authentication methods available (server sent: publickey), the Droplet could not locate the correct private SSH key file to authorize access for your local machine. For information on how to troubleshoot your SSH keys, see How and When to Troubleshoot SSH Issues.

what is Droplet Metadata? Metadata is a service provided to DigitalOcean Droplets that allows a Droplet to access data about itself
why you should upload your SSH public key to your account? This lets you log in to your servers without a password while still remaining secure
How to Create SSH Keys with OpenSSH on MacOS or Linux?

1- ssh-keygen
2-
Generating public/private rsa key pair. Enter file in which to save the key (/home/username/.ssh/id_rsa):
when above message appears you can press Enter to continue with prefered path which is ~/.ssh since Using the default locations allows your SSH client to automatically find your SSH keys when authenticating later
NOTE: 
If you have previously generated a key pair, you may see a prompt that looks like this:

/home/username/.ssh/id_rsa already exists.
Overwrite (y/n)?

If you choose to overwrite the key on disk, you will not be able to authenticate using the previous key anymore. Selecting yes is an irreversible destructive process.

3- 
Created directory '/home/username/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
in above message you can enter your desired passphrase but if you choose one (which is recommended) you should remember it always

How to Create SSH Keys with PuTTY on Windows? 1- you need to download and install both PuTTY and PuTTYgen, a utility used to create SSH keys
2- RSA algorithm is appropriate for most situations but since Fedora doesn’t accept RSA, so you can choose ECDSA
3- Copy generated public key (which is displayed in a textbox) into your clipboard
4- enter a passphrase for your SSH key
5- click the Save private key button and select a secure location to keep it (You can name your key whatever you’d like, and the extension .ppk is automatically added)
NOTE:
You can click Save public key as well, but take note: The format PuTTYGen uses when it saves the public key is incompatible with the OpenSSH authorized_keys files used for SSH key authentication on Linux servers

If you need to see the public key in the right format after the private key has been saved:

  1. Open PuTTYgen.
  2. Next to Load an existing private key file, click the Load button.
  3. Navigate to the private key in your file system and select it.
  4. Click Open.
what is entropy? “generate some randomness by moving the mouse over the blank area”
what does a passphrase do for you? improves security by preventing someone who gains access to your private key from using it without also knowing the passphrase
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

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