Generating SSL certs with ACF 1.9

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Revision as of 14:38, 20 November 2009 by Ttrask (talk | contribs) (Script is now setup-acf, not setup-webconf)
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Creating SSL certs using ACF

You are in need of creating certificate for remote persons. You might use something like openvpn or racoon for your vpn services.
But wouldn't it be nice to have some sort of way to...

  • create and manage certs
  • view all the certs you have given to everyone
  • revoke certs
  • review the certificate before you issue it
  • etc.

Alpine, via the ACF, has a nice web interface to use for this sort of job...

Installation Process

This will somewhat guide you through the process of creating this type of server.
It is suggested not to host this on your VPN gateway but to use another machine to generate your certificates.

Prepare hardware and install Alpine

Start by setting up a box that will serve as your openvpn-server.
Please read 'Installing_Alpine' for instructions on how to do this.

Install and configure ACF

Install the web front end to Alpine Linux, called ACF. You will be prompted to create the password for the ACF root user.


Install acf-openssl (ACF for openssl)

apk add acf-openssl

Now you should be ready to start browsing to your OpenVPN-server by using a web-browser at another computer.
Note: Assuming you have configured and attached this openvpn-server to a network.


Start by browsing to your openvpn-server by entering https://{ipaddr}/ in your browser and login. The user is 'root' and the password is as entered above.

Certificate Authority

Click on 'Certificate Authority' on the menu.
It should give you a page with 'System info' and a lot of red error messages.

Click on the [Configure] button at the bottom of the page to generate some initial configuration.

Go to the {Edit Defaults} tab and enter the values you want to become default (this information appears when you are creating new certificate requests).
Save your settings by clicking [Save].

Generate a certificate with ACF

Create the ca.crt

First we need to create the CA-certificate (this is the cert used when creating other certificates).

Now go to the {Status} tab.
Click [Generate] button to generate your CA-certificate.
The ca-certificate information will be displayed.

Note: This action can only be done once. In the future, the {Status} page will show the CA-information.
The [Generate] button will not exist any more.

Request Form

The {Request} form is used to create new certificate requests.

Fill in your values in the fields and finish your request with [Submit].

Provided Fields (based upon the default cnf file):

  • Country Name (2 letter abreviation)
  • Locality Name (e.g. city)
  • Organization Name
  • Common Name (eg, the certificate CN) <<< This name should be unique for this certificate
  • Email Address
  • Multiple Organizational Unit Name (eg, division)
  • Certificate Type
  • x509 extensions

Note: The x509 Etensions box should be formatted the same as if you were to fill out a section directly in openssl.cnf.
Section would be [v3_req]

x509 extensions example

[ v3_req ]
subjectAltName ="IP:"
subjectAltName ="DNS:"

Note: that x509 settings are optional. This is just a example!


The {View} tab gives you the possibility to:

  • View/Approve/Delete pending certificate requests
  • View/Download/Renew/Revoke/Delete approved certificates
  • View/Delete revoked certificates
  • Download list of revoked certs

Pending certificates

For a Pending request make sure to review the cert before approving it.
Once you have verified that all the information is correct, no mis-types or spelling mistakes Approve the request.

Download the .pfx

For each approved certificate you can download a .pfx file containing the certificate.
With this .pfx you can extract the certs that you will need.


Via the {Expert} tab you will be able to edit the '/etc/ssl/openssl-ca-acf.cnf' configuration file.
If you want to save your certs on USB-mem (or somewhere else), this is where you should do such change.

Something like subjectAltName can be added to be used by the certificates that you generate.

3.subjectAltName         = Assigned IP Address
3.subjectAltName_default =

Start using the PFX certificate

Extract PFX certificate

The next examples are executed by entering the commands on a console (not in ACF).
Extract the 'CA CERT' from the .pfx:

openssl pkcs12 -in PFXFILE -cacerts -nokeys -out cacert.pem

Extract the 'Private Key'

openssl pkcs12 -in PFXFILE -nocerts -nodes -out mykey.pem

Extract the 'Certificate'

openssl pkcs12 -in PFXFILE -nokeys -clcerts -out mycert.pem

View PFX certificate information

Display the cert or key readable/text format

openssl x509 -in mycert.pem -noout -text

OpenSSL command line to create your CA

The following command will need a password. Make sure to remember this.

openssl genrsa -des3 -out server.key 2048
openssl req -new -key server.key -out server.csr
openssl rsa -in server.key. -out server.pem
openssl x509 -req -days 365 -in server.csr -signkey server.pem -out cacert.pem
mv server.pem /etc/ssl/private
mv cacert.pem /etc/ssl/