Setup openSSH for Linux-to-Linux

This guide steps out how to set up openSSH, complete with an authenticating key pair, so that you can access your Linux VPS host securely from your home or office-based Linux PC.
For a little more theory behind the secure shell (SSH) protocol you may care to take a peek at vpsBible’s parallel Windows-to-Linux connection guides at Set Up Command Line Interface (CLI) using PuTTY and Encrypt Data with OpenSSH & Auto-Login with PuTTY.
Using this method you’ll have:-
- encrypted data/password transfer
- password-free login
- tighter server security ***
*** for this, we must also edit the sshd_config file. We’ll get to that in Harden the Secure Shell (SSH) & Create a Firewall.
USING WINDOWS locally? Then read this instead.
Setup Unmanaged VPS: The Ubuntu-Nginx Guide
Take your virtual private server from zero to hero
.. from blank box to cute-as server ..
with this easy-to-follow copy/paste guide.
22+ parts with video, here’s the index.
The SSH Protocol
The SSH protocol works by matching an authenticating key pair: a public one on your remote host and a private one on your local machine.
And What We’re Doing Now
We need to create those keys, upload the public one and connect remotely, password-free.
Access the Virtual Private Server
Open a remote connection from your terminal, KEEP IT OPEN in case of an error, so you can access remotely to correct the mistake. I’ll tell you when it’s safe to disconnect.
.. swapping username for your newly created username and hostname for your IP address.
As requested, provide your password.
Create Authentication Keys
Logged in locally, type this:-
.. you’ll be prompted where you want the keys to live: simply hitting return will create them in the hidden ssh directory in your ~/home folder. Alternatively, if when prompted you choose a bespoke filename without a path then they will be added to your ~/home folder so you’ll need to move them to your ~/home/.ssh folder, but first ..
Then you’re asked to create and confirm a passphrase. You can leave that blank but, IMHO, don’t. Make it original, several words long and mix up with some special characters for Fort Knox security. For example:
.. or, to be just ridiculously safe ..
So you’ve got 2 authentication keys, a nice pair. To copy the public key to the remote machine:-
- SCP is the program Secure Copy, which you can read all about here – Backup or Upload with Secure Copy SCP (Linux/Linux)
- ~/.ssh/id_rsa.pub is the public key file, which has been created in your home user folder, in the new .ssh directory
- username is your remote host username
- hostname.com is either your hostname, else the IP address
- : tells SCP we’re about to detail a remote location
- /home/username/ is the remote destination folder
Problems with SCP?
Most likely you can ignore this. But! Should you find you are having problems using SCP, read this ..
- First, get clued up on SCP by reading that link I mentioned.
- Failing that, bugger SCP! Do this instead:-
Logged in locally, let’s print the key on the terminal screen by pasting this:-
.. copy that; your public authentication key.
Now, logged in remotely, paste it to a new file which we’ll create with SuperUser permissions, using the Nano text editor:-
Right, whether using SCP or not, that’s your public key up on the server. No slacking, carry on ..
Just to back up a little, let me clarify. What we have done is to create those keys and pop one up to the server. But, er, it’s in the wrong place! Let’s sort that out.
On the remote server, create a new folder, then we’ll move that public key to it and set some file permissions:-
- mkdir /home/username/.ssh is the place for user-specific keys
- mv so we move this key there
- chown -R username:username and change ownership of user and group
- chmod 700 ~/.ssh giving the owner read/write/execute rights to the .ssh folder
- chmod 600 ~/.ssh/authorized_keys and read/write permissions to the keys folder
Login Using Authentication Keys
So now we can login remotely, using those authentication keys:-
You’ll be prompted for your passphrase (even if it says password), and asked if you want to store it (by your local machine, or is that just with thoroughly-friendly Ubuntu Desktop? .. I’m not sure.) If you store it, you’ll not need it again until you reinstall or buy a new rig. If you don’t store it, you’ll have to input the passphrase once per local session login.
After that, whenever you ssh into remote, depending on the passphrase storage preference, you’ll be logged in immediately without having to give any further details.
Now then. Tell me – as well as being secure and encrypted – isn’t just so darned cool?
Setup Unmanaged VPS: The Ubuntu-Nginx Guide
Take your virtual private server from zero to hero
with this easy-to-follow copy/paste guide.
“My local PC runs Windows” Show me for Linux
“My local PC runs Linux” Show me for Windows
22+ parts with video, here’s the index ..
-
Setup Unmanaged VPS: The Ubuntu-Nginx Guide
Introducing vpsBible’s how-to guide for setting up a super-charged unmanaged VPS featuring Ubuntu and Nginx.
-
VPS (Virtual Private Server) vs Shared vs Dedicated
Before getting stuck in, let’s compare the web host types in detail and weigh up the differences between managed & unmanaged VPS.
-
Set Up a VPS Linux Distribution
Opening a VPS hosting account, we’ll choose, configure & launch a Linux server ‘distribution’.
-
Set Up Command Line Interface (CLI) using PuTTY
Now we’ve got a server to play with, we’ll connect to it, using the ’ssh’ protocol for a super-secure link.
-
Create a Linux User & Set Permissions
Initially you’ve logged into your remote Linux machine as ‘root’. We’ll add you as a user now, with root or SuperUser permissions.
-
Encrypt Data with OpenSSH & Auto-Login with PuTTY
Now we can use ‘authentication keys’ to shore up our connection while simplifying login to an automated, password-free yet secure process.
-
Harden the Secure Shell (SSH) & Create a Firewall
The final security step: galvanizing the OpenSSH protocol and setting up an ‘iptables’ firewall. Now the server is rock ruddy solid.
-
Edit bashrc for User-Friendly Linux, plus System Updates
We use the terminal a whole lot so let’s cut ourselves a break and create some command shortcuts, then update the server.
-
Add a Domain Zone to Your VPS
To make your server aware of yourDomain.com you’ll need a few ‘DNS’ records. Damn this is simple I’m practically asleep!
-
Prepare Linux Server for Email with Postfix
In order to send and receive email from our web applications we’ll install some software and tweak the ‘RDNS’ record.
-
Install PHP5 & MySQL – The One-Stop FastCGI Index Page
Add PHP5 & MySQL, but which FastCGI method is best? Here’s the benchmarking, 4 ways to install/compile, add caching modules & more.
-
Nginx (better than Apache) Web Server
Let’s install this supersonic web server, tweaking its file structure & adding default configuration files.
-
Setup FileZilla for Secure FTP (SFTP)
There’s FTP, and then there’s ‘Secure FTP’. We’ll set up FileZilla using SFTP – and those authentication keys – for secure file transfers.
-
Serve Multiple Sites & Blogs with Virtual Hosts
We want a website folder structure, some permissions, some site-specific configuration files and, hey, we’ll hook up ‘FastCGI’.
-
Adding Sub-Domains with Nginx
Need a sub-domain? If you do, here’s how to add subDomain.yourSite.com with an ‘A record’ and a configuration file.
-
Integrate A CMS Like WordPress, WP MU, Drupal etc
For those of you wanting to use a specific content framework, such as a CMS, blogging or forum software, pop in here and we’ll sort that out.
-
Google Apps for Domain-Specific Email
GA’s free Standard Edition for catchall webmail – POP-ping or IMAP-ped to your desktop client – saves precious server resources for your webs.
-
Moving Day! How to Move Your Blog or Site
Nearly there. Here’s the web site or blog migration guide, relocating to your VPS with minimal or no downtime.
Manage Unmanaged VPS: Ubuntu-Nginx Administration
Already set it up? We’d best maintain it then.
Toggle to the .. Ubuntu-Nginx Admin Index
Manage Unmanaged VPS: Ubuntu-Nginx Administration
Maintain your virtual private server with ..
.. cheatsheets, tutorials, tips & guides.
Head back to the .. Ubuntu-Nginx Installation Index
-
Nginx Control Panel: Here’s the Deal
You’re migrating shared-to-VPS and want a GUI like cPanel? No you don’t, not after you read this! What’s more, you don’t need one either.
-
Nginx Control Panel Workarounds
For every control panel module there’s an equivalent (and faster) terminal command. Let’s compare these.
-
Upgrade to Nginx Latest Version with ZERO Downtime
Keep Nginx up-to-date – and optimized for security. This guide shows precisely how *with no missed server requests*.
-
Compile an Advanced Nginx Module Configuration
Need special web server functions? Here’s how to install or upgrade Nginx with bespoke required modules & parameters.
-
Add Web Sites Nginx Cheatsheet
Once you’ve set up your first site, adding more gets easier. Especially when you refer to this. (Let’s face it, I’m just too good to you.)
-
Adding Sub-Domains with Nginx
Rather than add somesite.tld, maybe you want some.subsite.tld? Here’s how to set your A record using a DNS manager and the vhost file for Nginx.
-
Add/Delete MySQL Database from Command Line
Need a database? Want to bin an old db? This tutorial shows you how using the terminal command line console whatnot.
-
Configure phpMyAdmin for Nginx to Maintain MySQL
Rather than have to crunch databases via the command line, we can make life easier by adding this splendid tool to manage them.
-
Backup/Export MySQL DB with CLI & mysqldump
Here’s how to backup a database from the command line using the handy mysqldump utility.
-
Import MySQL Database using Command Line
Import data to a new database with this simple mysqldump guide .. great for reinstating an old backed-up db, for instance.
-
Batch Replace/Delete Data in MySQL Database
Change repetitive db data with a single command. Rather than manually find & alter each instance, isolate the lot & update multiple content.
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LOST a MySQL Password? How to RESET it
Lost your MySQL password? That’s a bit of a bummer .. or it would be if you didn’t have this new password setup guide, huh.
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Backup or Upload with Secure Copy SCP (Linux to Linux)
Never mind FTP m8! Save time and download/upload your files using encrypted SCP (secure copy), the #1 Linux-Linux file transfer solution.
-
Backup or Upload with PuTTY PSFTP (Windows/Linux)
Equivalent to the above, how to transfer your files if you’re unlucky enough to be running Windows for your local PC. Not that I’m biased.
-
*USEFULLY* Park A Spare Domain with Nginx
Got a spare domain name sat around doing nothing? Put it to some use, have it point its traffic at your primary domain. Here’s the deal ..
-
Password Protect Nginx Web Files/Directories
Maybe you want a hidden website directory, say, for projects, or are developing a site and want it off-limits ’till launch day. Top tip ..
-
Redirect Web Pages with Nginx Rewrite Rule
Here’s the syntax to point a site or blog to another domain. That way, for instance, traffic from a passive site benefits an active one.
-
Nginx Error & Access Logs
Need to troubleshoot some error, or want to find out who’s trying to hack your site? Here’s a start .. those tell-tale logs.
-
Subversion for Easy CMS Updates ie WordPress/Drupal/etc
A brief introduction to install and know about the power of Subversion, the version control system to keep scripts and platforms up-to-date.
-
You Tell Me …
Something missing? Probably. Let me know what you’d like included. And if it’s listed below, shout out anyhow and I’ll try to bump it.
Nginx Admin: In the Works ..
This lot’s marked for addition already:-
- Setup or Edit DNS using Bind
- Network Tools Troubleshooting Guide
- The Comprehensive Permissions Guide
- Configuring Nginx Rewrites
- Custom Website Error Page
- Setting up Cron Jobs
- Rsync for Incremental Remote-to-Local Backup
- Cron & Rsync for Automatic Backup
- Cron & mysqldump for Auto DB Backup
- Safeguard Bandwidth with Hotlink Protection
- Block Access with Nginx’ IP Deny
Install openSSH guide generating & authentication keys to boost server security, encrypt data transfer & make login password-free from a Linux PC.
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