Linux Crash Course - Public Key Authentication

Public Key Authentication with OpenSSH is preferred, as it's a much stronger method of authenticating to your servers when compared to using password authentication. In fact, password authentication in OpenSSH should always be disabled. But before you can password authentication, you'll need to set up public key authentication, and that's exactly what we'll do in today's video.

# Helpful OpenSSH content to take your knowledge even further:
🐧 Locking down OpenSSH (goes over disabling password authentication):

🐧 Full OpenSSH Guide (goes over even more detail than this):

# Timecodes:
00:00 - Intro
02:32 - Checking if the OpenSSH client is present (Linux)
03:10 - Checking if the OpenSSH client is installed (MacOS)
03:44 - Installing PuTTY (Windows 10)
05:12 - Generating an SSH keypair (Linux and macOS)
08:40 - Testing OpenSSH connectivity (Linux and macOS)
09:30 - Copy the public key over to a remote server (Linux and macOS)
12:09 - Setting up a session for a server in PuTTY for Windows
13:38 - Creating an SSH key pair in Windows with PuTTYgen
15:40 - Using a PEM key to connect to a Linux server via PuTTY in Windows 10

*VIDEO SPECIFIC LINKS*
💻 Download PuTTY:

# About Me
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*📘 FAQ*

#SSH #OpenSSH #Linux

[blkspade]

The SSH client has been a standard part of Windows 10 for quite some time now.

[Ranblv]

I am very inspired by how much you give back to the linux community. so today I started my own linux blog in my language. not sure how long I will last but I made the first step.

[ralpht]

Win10 since 1604 i think, also supports SSH in cmd.

[cip]

the best professor from the entire internet !!! THANK YOU!!!

[praecorloth]

Hey Jay! Quick side note. Windows 10 does come with OpenSSH by default now. I forget which update brought it in, but Microsoft ported OpenSSH to Windows. The client is there by default, and you can install the server portion really easily. Just fire up a cmd or Powershell prompt, and ssh wherever you'd like to go. The ssh agent doesn't seem to be working yet, they have that disabled by default. And Windows won't use Pagent, so using keys properly can be quite the nuisance. But, then again, working in Windows in general is just a nuisance. :D

This opens up the ability to manage your Windows servers using Ansible and SSH, rather than Ansible and...shudder...WinRM.

[ClifBridegum]

AMAZING! This tutorial is perfect! I have been struggling big time with how to generate and share keys. Thanks for covering all platforms.

[diablobarcelona]

Would be really nice to for you to do a video on SSH User Certificates. They're absolutely superb, and make light work of managing users access to systems via SSH keys.

[whatevah]

nice, something that would be cool if you could do a tutorial on is how one can log onto linux via ldap and use groups for giving user sudo access and all that jazz, thanks!

[try-that]

Just started watching, gotta say I like the new opening, very nicely thought out and done.

[NoEggu]

@7:04 -- Setting a passphrase

What would you need to do, if you did set a passphrase, but sometime later, you want to change your passphrase?
Would you need to generate a new key pair, and upload the your new public key, to every server that has your old passphrase?

[zm_gawr]

I have put elementary os on my old macbook from 2008 but the keys are completely wrong, do you know how my mac keys(cmd, alt, ctrl) work on elementary os?

[christosbinos]

does anyone run into the issue where the password is simply never correct, when you know it is? What is thst caused by?

[viliusk]

Winodow 10 Pro has ssh client, and ssh-keygen

[NinthwaveThe]

At 14:40, why would one create a notepad file to save the public key if it's available within the PuttyGen when loading back the private key ?

[benjaminwharton]

Thanks for the content!! This helped a lot.

[ArtyomGalstyan]

Does not work for me. I did everything correct, but the server still asks for the password. I checked file permissions, checked the config files, basically did everything, but it still does not work. Even chatgpt did not help.

[flyingzeppo]

I have a question about setting up PKA. If you do this, and disable password authentication, then what happens if your laptop blows up or gets stolen? Wouldn't you be locked out of your server forever? If you can only access your server through PKA, and you lose your computer that has the private key on it, then what happens?

[soniablanche]

ssh comes with windows 10 and is usable with powershell

[cloudagnostic]

Hi jay, I’ve implemented keys to connect to my servers in my lab, but I also make changes to the ssh config file to disable the pw prompt if someone tries to log in. Is that still necessary following this method?

[NinthwaveThe]

At 5:45, you mention that ssh-keygen will overide the actual one, if any.
But you don't mention the consequences of that...
If one is already there and you create a new one, is it a problem if you then copy the new key to the server ?