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diff --git a/sshadvanced.html b/sshadvanced.html new file mode 100644 index 0000000..33d9cb0 --- /dev/null +++ b/sshadvanced.html @@ -0,0 +1,131 @@ +<!DOCTYPE html> +<html lang=en> +<head> + <title>SSH - Advanced Usage – LandChad.net</title> + <meta charset="utf-8" /> + <link rel="shortcut icon" href="favicon.ico" type="image/x-icon" /> + <link rel='stylesheet' type='text/css' href='style.css'> + <meta name="viewport" content="width=device-width, initial-scale=1"> + <link rel='alternate' type='application/rss+xml' title='Land Chad RSS' href='/rss.xml'> +</head> +<body> + <header> + <h1>SSH - Advanced Usage</h1> + </header> + <nav></nav> + <main> + <h2>Introduction</h2> + <p> + This page is dedicated to advanced SSH usage examples. We will discuss the following concepts: + <ul> + <li>config files (for client)</li> + <li>tunneling</li> + <li>jumping</li> + </ul> + </p> + <h2>Config files</h2> + <p> + Config files allow you to specify certain rules for all or chosen hosts. The file has a really simple structure. + It is divided into sections which begin with the <code>Host</code> keyword. Sections are read one by one and <b>the first + matching section takes precedence over the remaining sections</b> - you write more specific sections at the top and the more general + sections below. + </p> + <h3>Why even bother?</h3> + <p> + You might say that SSH client doesn't need any special configuration - you just type the user@host and that's it. + Well, what happens when you manage multiple servers? Maybe you want to use a different pair of keys for each servers? + Maybe the server uses a port other than the default 22 to avoid automated bots trying to log in? + </p> + <p> + That's where config files come in handy! + </p> + <h3>Example scenario</h3> + <p> + Let's assume that you manage 3 servers, with the following access info: + <ol> + <li>very.long.hostname.example1.com + <ul> + <li>user: admin</li> + <li>port: 22</li> + <li>key name: id_rsa</li> + </ul> + </li> + <li>example2.com + <ul> + <li>user: billthemaster</li> + <li>port: 2222</li> + <li>key name: example2_ecdsa</li> + </ul> + </li> + <li>192.168.133.7 + <ul> + <li>user: management</li> + <li>port: 22</li> + <li>key name: id_rsa</li> + </ul> + </li> + </ol> + </p> + <p> + You got tired having to always specify the identity file location with the <code>-i</code> option and the port with <code>-p</code> option for example2.com. + Don't even mention <code>admin@very.long.hostname.example1.com</code>! + </p> + <p>In the given example, the config file could look like this: +<code><pre>Host server1 + HostName very.long.hostname.example1.com + User admin + IdentityFile ~/.ssh/id_rsa + +Host server2 + HostName example2.com + Port 2222 + User billthemaster + IdentityFile ~/.ssh/example2_ecdsa + +Host server3 + HostName 192.168.133.7 + User management + IdentityFile ~/.ssh/id_rsa + +Host * + IdentityFile /path/to/some/other/key +</pre></code> + </p> + <p>You can see here usage of <code>Host *</code>. Options specified in this section will affect all other hosts.</p> + <h3>But where do I put this file?</h3> + <p> + SSH looks for the options in the following order: + <ol> + <li>command line arguments</li> + <li><code>~/.ssh/config</code></li> + <li><code>/etc/ssh/ssh_config</code></li> + </ol> + </p> + <p>You can also specify a custom path with the <code>-F</code> argument, for example: + <code><pre>ssh -F ~/Documents/projects/someproject/config/ssh production</pre></code> + </p> + <p> + ...or discard any config file: + <code><pre>ssh -F /dev/null username@hostname</pre></code> + </p> + <p>There's more to ssh config files, but I direct you to <code>man ssh_config</code> for more information</p> + </main> + <footer> + <a href="https://landchad.net">LandChad.net</a> + </br>Because Everyone should be an Internet LandChad.</br> + <a href="index.html"> + <li><img src="pix/chad.gif" alt="chad"></li> + </a> + <a href="rss.xml"> + <li><img src="pix/rss.svg" alt="RSS"></li> + </a> + <a href="pix/btc.png"> + <li><img src="pix/btc.svg" alt="BTC"></li> + </a> + <a href="pix/xmr.png"> + <li><img src="pix/xmr.svg" alt="XMR"></li> + </a> + <a href="https://github.com/lukesmithxyz/landchad"> + <li><img src="pix/git.svg" alt="Github"></li> + </a></footer> +</body>
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