How to Set Up VPN Certificates

For the VPN service, you can use either self-signed certificates or certificates that are generated by an external CA.

In this article:

Before You Begin

Before you set up VPN certificates, verify that the VPN service has been properly created and configured. For more information on how to create a service, see How to Configure Services.

Set Up Certificates with the Barracuda CA for a Barracuda VPN

If you want to use a Barracuda VPN with the Barracuda CA installed on the Barracuda NextGen Firewall F-Series, complete the following steps:

Step 1. Create the Default Certificate and Private Key

The default server certificate will be signed by the self-signed Barracuda root certificate that is included with the Barracuda NextGen Firewall F-Series.

1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > VPN Settings.
2. Click Lock.
3. Click the Settings tab.
4. Click the Click here for Server Settings link. 
5. If you are using the Access Control service, enter its IP Address in the Access Control Service section of the Server Settings window. 
6. Create the certificate:
   1. In the Default Server Certificate section, click Ex/Import and select New/Edit Certificate.

   2. In the Certificate View window, fill out the Subject section completely. You must set the SubAltName and Name to the FQDN resolving to the listening IP address of the VPN service.

   3. Click OK.

7. Create the default key:
   1. Click Ex/Import in the Default Key section.
   2. Select New x-Bit RSA key (where x is 512, 1024, or 2048).
   3. Click OK.
8. Click Send Changes and Activate.

Step 2. Import the Default Certificate and Private Key

1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > VPN Settings.
2. Click Lock.
3. Click the Settings tab.
4. Click the Click here for Server Settings link.
5. If you are using the Access Control Service (NAC), enter its IP Address in the Access Control Service section of the Server Settings window. 
6. In the Default Server Certificate section, click Ex/Import and select either Import PEM from file or Import from PKCS12, depending on the external certificate format.
7. In the Default Key section, click Ex/Import and select Import Private Key from File.
   If the certificates match, the Default Server Certificate and the Default Server Key display 'Valid' in green.
   
8. Click OK.
9. Click Send Changes and Activate.

Set Up Certificates with an External CA for a Barracuda, IPsec, or L2TP/IPsec VPN

Requirements

Install the Root Certificate

1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > VPN Settings.
2. Click Lock. 
3. Click the Root Certificates tab. 
4. Right-click the table and select Import PEM from File or Import CER from File, depending on the root certificate format. 
5. In the Open window, select the root certificate file and click Open.
6. In the Root Certificate window, configure the following settings under the Certificate details tab:
   • Name – A descriptive name for the root certificate. For example, RootCert.
   • Usage – The types of VPNs that will use this root certificate. For example, Barracuda Personal and IPsec Personal.
7. Click OK.

The root certificate appears under the Root Certificates tab.

Install the Server Certificate

1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > VPN Settings.
2. Click Lock.
3. Click the Server Certificates tab.
4. Import the server certificate.
   1. Right-click the table and select Import Certificate from File.
   2. In the Open window, select the server certificate file and click Open.
   3. Enter the Certificate Name, for example, ServerCertificate, and then click OK. The certificate appears under the Server Certificates tab.
5. Import the private server key.
   1. Right-click the server certificate and select Import Private Key From File.
   2. In the Open window, select the private server key file, for example, ServerCertprivate.pem, and then click Open.
6. Click Send Changes and Activate.

Your server certificate appears with the private key in the Server Certificates list.

Create a Service Certificate/Key

1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > VPN Settings.
2. Click Lock.
3. Click the Service Certificates/Keys tab.
4. Right-click the table and select New Key. 
5. Enter a Key Name, and click OK.
6. Select the required Key Length, and click OK.
7. Click Send Changes and Activate.

Your service certificate appears under the Service Certificates/Keys tab.

Create a CSR on the Barracuda NextGen Firewall F-Series

You can create a certificate signing request (CSR) directly on the command line of the Barracuda NextGen Firewall F-Series.

1. Go to SSH and login.

2. On the command line enter:

   openssl req -new -newkey rsa:2048 -nodes -keyout domain.key -out domain.csr

3. Download the certificate to your desktop:

   [down] domain.csr
4. Save the csr file to your disk. 

You can now submit the certificate signing request to your CA to receive a signed certificate.

Certificate Detail Settings

From the Certificate details tab, you can configure the following settings:

• Certificate – The certificate's subject and issuer.
• Name – The certificate name for easier recognition.
• Usage – The tunnel types that the certificate is valid for. The following tunnel types are available:
  • Personal
  • Site-to Site
  • IPSec Personal
  • IPSec Site-to-Site
• Comment – An optional description of the certificate.
• Timeout (min.)  – The length of time after which the fetching process is started again if all URIs of the root certificate fail.
• Action – The action that is taken if the CRL is not available after the fetching process that is started after the Timeout. You can select one of the following actions:
  • Terminate all sessions – Every VPN session relating to this root certificate is terminated.
  • Do not allow new sessions – New VPN sessions relating to this root certificate are not allowed.
  • Ignore – A log entry is created but does not have any effect on VPN connections relating to this root certificate.

Certificate Revocation Settings

From the Certificate details tab, you can either import or manually add a CRL URI.

1. If a CRL is already included within the certificate, import the CRL URI by clicking Load paths from certificate.
2. To add a CRL URI manually, configure the settings in the URI, Login, and Proxy sections and then click Add.
3. Protocol – The required connection protocol. The following protocols are available:
   • LDAP – DNS-resolvable, default port: 389
   • LDAPS – DNS-resolvable, default port: 636
   • HTTP – Default port: 80
   • HTTPS – Default port: 443
4. Host – The DNS-resolvable host name or IP address of the server that makes the CRL available.

5. URL-Path – The path to the CRL. For example: cn=vpnroot,ou=country,ou=company,dc=com?,cn=*

   When the CRL is made available through SSL-encrypted LDAP (LDAPS), use the fully qualified domain name (that is the resolvable host name) in the CN subject to refer to the CRL. For example, if a server's host name is server.domain.com, enter the following in the URL path: cn=vpnroot,ou=country,ou=company,dc=com, cn=server.domain.com

   The A-Trust LDAP server requires the CRL distribution point referring to it to terminate with a CN subject. Therefore, as from Barracuda NextGen Firewall F-Series 3.6.3 when loading the CRL from a certificate, the search string "?cn=*" will automatically be appended if the CRL is referring to an LDAP server and if a search string (CN subject) is not available in the search path by default. Note that existing configurations will remain unchanged and that the wildcard CN subject does not conflict with other LDAP servers.

• User / Password – The username and corresponding password. This information is necessary if the LDAP or HTTP server requires authentication.
• Proxy – The DNS-resolvable host name or IP address of the proxy server.
• Port – The proxy server port used for connection requests.
• User / Password – The username and corresponding password. This information is necessary if the proxy server requires authentication.

From the OCSP tab, you can configure the following settings:

• Host – The DNS-resolvable hostname or host IP address.
• Port – The OCSP server listening port. Use SSL – Enforces an SSL connection to the OCSP server.
• Phibs Scheme – Allows selection of an OCSP scheme (default: ocsp).  CA Root – Specifies how the OCSP server is verified. You can select the following options:
  • This root certificate – The OCSP server certificate signing the OCSP answer was issued by this root certificate.
  • Other root certificate – The OCSP server certificate signing the OCSP answer was issued by another root certificate. This other root certificate must be imported via the Other root setting.
  • Explicit Server certificate – The OCSP server certificate signing the OCSP answer might be self-signed or another certificate. This X.509 certificate must be imported via the Explicit X.509 setting.

• Other root – If CA Root is set to Other root certificate, click Ex/Import to import the certificate in either PEM or PKCS12 format.
• Explicit X509 – If CA Root is set to Explicit Server, click Ex/Import to import the certificate in either PEM or PKCS12 format.