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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><title>TLS-protected syslog: scenario</title>
</head>
<body>
<h1>Encrypting Syslog Traffic with TLS (SSL)</h1>
<p><small><i>Written by <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer
Gerhards</a> (2008-06-17)</i></small></p>
<ul>
<li><a href="rsyslog_secure_tls.html">Overview</a>
<li><a href="tls_cert_scenario.html">Sample Scenario</a>
<li><a href="tls_cert_ca.html">Setting up the CA</a>
<li><a href="tls_cert_machine.html">Generating Machine Certificates</a>
<li><a href="tls_cert_server.html">Setting up the Central Server</a>
<li><a href="tls_cert_client.html">Setting up syslog Clients</a>
<li><a href="tls_cert_udp_relay.html">Setting up the UDP syslog relay</a>
<li><a href="tls_cert_summary.html">Wrapping it all up</a>
</ul>
<h3>Setting up the CA</h3>
<p>The first step is to set up a certificate authority (CA). It must be
maintained by a trustworthy person (or group) and approves the indentities of
all machines. It does so by issuing their certificates. In a small setup, the
administrator can provide the CA function. What is important is the the CA's
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private key is well-protocted and machine certificates are only issued if it is
know they are valid (in a single-admin case that means the admin should not
issue certificates to anyone else except himself).</p>
<p>The CA creates a so-called self-signed certificate. That is, it approves its
own authenticy. This sounds useless, but the key point to understand is that
every machine will be provided a copy of the CA's certificate. Accepting this
certificate is a matter of trust. So by configuring the CA certificate, the
administrator tells <a href="http://www.rsyslog.com">rsyslog</a> which certificates to trust. This is the root of all
trust under this model. That is why the CA's private key is so important -
everyone getting hold of it is trusted by our rsyslog instances.</p>
<center><img align="right" src="tls_cert_ca.jpg"></center>
<p>To create a self-signed certificate, use the following commands with GnuTLS (which
is currently the only supported TLS library, what may change in the future): </p>
<ol>
<li>generate the private key:
<pre>certtool --generate-privkey --outfile ca-key.pem</pre>
<br>
This takes a short while. Be sure to do some work on your workstation,
it waits for radom input. Switching between windows is sufficient ;)
</li>
<li>now create the (self-signed) CA certificate itself:<br>
<pre>certtool --generate-self-signed --load-privkey ca-key.pem --outfile ca.pem</pre>
This generates the CA certificate. This command queries you for a
number of things. Use appropriate responses. When it comes to
certificate validity, keep in mind that you need to recreate all
certificates when this one expires. So it may be a good idea to use a
long period, eg. 3650 days (roughly 10 years). You need to specify that
the certificates belongs to an authority. The certificate is used to
sign other certificates.<br>
</li>
</ol>
<h2>Copyright</h2>
<p>Copyright (c) 2008 <a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer
Gerhards</a> and
<a href="http://www.adiscon.com/en/">Adiscon</a>.</p>
<p> Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version
1.2 or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license can be viewed at
<a href="http://www.gnu.org/copyleft/fdl.html">http://www.gnu.org/copyleft/fdl.html</a>.</p>
</body></html>
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