Difference between revisions of "Cool Solution - Let's Encrypt"

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{{Version|UCS=4.2}}
 
{{Cool Solutions Disclaimer|Repository=yes}}
 
{{Cool Solutions Disclaimer|Repository=yes}}
This article explains how to install a small Let's Encrypt client using the "ACME" protocoll by running a wrapper script, which UCR variables must be configured and how to obtain the certificates.
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Follow these instructions to setup certificates issued by [https://letsencrypt.org/getting-started/ Let's Encrypt] Certificate Authority in your UCS servers. For example to enable HTTPS in you website. Or for [http://sdb.univention.de/content/15/230/en/using-your-own-ssl-certificates.html other services] offering SSL/TLS encrypted communication.
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This article explains how to install a small Let's Encrypt client from our [http://wiki.univention.de/index.php?title=Category:Cool_Solutions_Repository cool solution repository] to generate and renew your TLS certificates, and how to configure different services to use them. The client uses the [https://letsencrypt.org/how-it-works/ "ACME"] protocol to negotiate with Let's encrypt servers.
  
 
__TOC__
 
__TOC__
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== Requirements ==
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* A valid DNS A record pointing to the public IP Address of your UCS server. For example, if the goal is to issue a certificate for service1.example.com, that server should be resolvable from the Internet:
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You need an A record pointing to a public IP Address:
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<syntaxhighlight lang="bash" >
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host -t A service1.example.com   
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service1.example.com has address 1.2.3.4
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</syntaxhighlight>
  
 
== Installation ==
 
== Installation ==
After installing the package <code>univention-letsencrypt</code> the client is ready for configuration:
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<syntaxhighlight lang="bash" line="1">
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Install the letsencrypt client:
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<syntaxhighlight lang="bash">
 
univention-install univention-letsencrypt
 
univention-install univention-letsencrypt
 
</syntaxhighlight>
 
</syntaxhighlight>
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After installing the package <code>univention-letsencrypt</code> the client is ready for configuration.
  
 
== Configuration ==
 
== Configuration ==
The package brings a new UCR variable which is read by the wrapper script from <code>univention-letsencrypt</code>. By default, <code>letsencrypt/domains</code> is empty and <code>letsencrypt/services/*</code> are set to 'no'.
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The package brings new UCR variables which are read by the scripts in <code>/usr/share/univention-letsencrypt/</code>. By default, <code>letsencrypt/domains</code> is empty and <code>letsencrypt/services/*</code> are set to 'no'.
 
{| class="wikitable"
 
{| class="wikitable"
 
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== Obtaining the certificate ==
 
== Obtaining the certificate ==
Run the script <code>'''/usr/share/univention-letsencrypt/setup-letsencrypt'''</code> to automatically register an account, create the needed files and start the certificate creation and validation for the domains saved in the UCR variable '''letsencrypt/domains'''. The script installs a cronjob that periodically checks if the certificates must be renewed. All actions from the script are written into a the log file <code>/var/log/univention/letsencrypt.log</code>.
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Set the <code>letsencrypt/domains</code> before running the setup script:
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<syntaxhighlight lang="bash">
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ucr set letsencrypt/domains="service1.example.com"
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</syntaxhighlight>
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Run the setup script <code>'''/usr/share/univention-letsencrypt/setup-letsencrypt'''</code> to automatically register an account, create the needed files and start the certificate creation and validation for the domains saved in the UCR variable '''letsencrypt/domains'''. The script installs a cronjob that periodically checks if the certificates must be renewed. All actions from the script are written into a the log file <code>/var/log/univention/letsencrypt.log</code>.
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<syntaxhighlight lang="bash">
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/usr/share/univention-letsencrypt/setup-letsencrypt
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</syntaxhighlight>
  
 
The certificate is saved in the directory <code>/etc/univention/letsencrypt</code>.
 
The certificate is saved in the directory <code>/etc/univention/letsencrypt</code>.

Revision as of 10:58, 22 June 2017

Produktlogo UCS Version 4.2

Note: Cool Solutions are articles documenting additional functionality based on Univention products. Packages provided by a Cool Solutions Repository are built by Univention, but will not be maintained. Not all of the shown steps in the article are covered by Univention Support. For questions about your support coverage contact your contact person at Univention before you want to implement one of the shown steps.

Also regard the legal notes at Terms of Service.

Follow these instructions to setup certificates issued by Let's Encrypt Certificate Authority in your UCS servers. For example to enable HTTPS in you website. Or for other services offering SSL/TLS encrypted communication.

This article explains how to install a small Let's Encrypt client from our cool solution repository to generate and renew your TLS certificates, and how to configure different services to use them. The client uses the "ACME" protocol to negotiate with Let's encrypt servers.

Requirements

  • A valid DNS A record pointing to the public IP Address of your UCS server. For example, if the goal is to issue a certificate for service1.example.com, that server should be resolvable from the Internet:

You need an A record pointing to a public IP Address:

host -t A service1.example.com    
 service1.example.com has address 1.2.3.4

Installation

Install the letsencrypt client:

univention-install univention-letsencrypt

After installing the package univention-letsencrypt the client is ready for configuration.

Configuration

The package brings new UCR variables which are read by the scripts in /usr/share/univention-letsencrypt/. By default, letsencrypt/domains is empty and letsencrypt/services/* are set to 'no'.

UCR Variable Description Example
letsencrypt/services/apache2 Whether the Apache2 webserver should be configured automatically or not, valid values are "Yes" or "No"
letsencrypt/services/postfix Whether the postfix service should be configured automatically or not, valid values are "Yes" or "No"
letsencrypt/services/dovecot Whether the dovecot service should be configured automatically or not, valid values are "Yes" or "No"
letsencrypt/domains A list of DNS names on which the server is reachable, separated by spaces service1.example.com service2.example.com

Obtaining the certificate

Set the letsencrypt/domains before running the setup script:

ucr set letsencrypt/domains="service1.example.com"

Run the setup script /usr/share/univention-letsencrypt/setup-letsencrypt to automatically register an account, create the needed files and start the certificate creation and validation for the domains saved in the UCR variable letsencrypt/domains. The script installs a cronjob that periodically checks if the certificates must be renewed. All actions from the script are written into a the log file /var/log/univention/letsencrypt.log.

/usr/share/univention-letsencrypt/setup-letsencrypt

The certificate is saved in the directory /etc/univention/letsencrypt.

At the end, setup-letsencrypt checks the three service UCR variables and, if one is found set to "Yes", runs the needed scripts from the setup.d and post-refresh.d directories to configure the Apache2 webserver, postfix, or dovecot. Additional services can be configured by placing appropriate configuration scripts into these directories.

When the list of domains in letsencrypt/domains changes and setup-letsencrypt is run again, a prompt asks for deleting the current csr-file and recreates it with the new UCR variable's content.

Certificate update

The lifetime of the certificates issued by Let's Encrypt is limited to 90 days. By default, a cron job of univention-letsencrypt will update the certificate on the first day of every month at 3:30am. Services (like postfix, dovecot, apache) that have been setup via univention-letsencrypt will be restarted automatically during this process. The cron interval can be adjusted via the UCR variable letsencrypt/cron. If unset, the value 30 3 1 * * is used.

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