We use cookies on our website to ensure we provide you with the best experience on our website. By using our website, you agree to the use of cookies for analytics and personalized content.This website uses cookies. More Information
It seems like your browser didn't download the required fonts. Please revise your security settings and try again.
Barracuda CloudGen Firewall

Authentication, Encryption, Transport, IP Version, and VPN Routing

  • Last updated on

VPN clients must authenticate themselves to the VPN server. A valid certificate is required for the client to verify the identity of the VPN server. To meet the security needs of your network, you can define username/password authentication and strict certificate requirements.

The firewall supports multiple encryption algorithms for VPN connections. For TINA VPNs, multiple transport types are also available.

VPN Authentication Certificates

X.509 certificates are used by IPsec, L2TP/IPsec, and TINA, the Barracuda proprietary transport protocol. The certificates contain the following information:

  • Public key.
  • Some data signed by the private key for verification. 
  • Identity of the the CA.
  • Identity of the owner.
  • Key usage. Depending on what type of VPN and which clients you use, certain X.509 extensions might be required when creating the certificate.

For PPTP VPNs, external certificates are not needed because certificates are generated by the server at run time.

Certificate CA (PKI) Options

A full-featured public key infrastructure (PKI) for self-signed certificates is included with the Control Center (C610,VC610, or VC820).

Use an external CA (PKI) for firewalls that are stand-alone or managed with a Control Center C400 or VC400.

Depending on the certificate, you must export it in one of the following formats after it is created and signed:

Certificate File Format
Root Certificate PEM or CER
Server Certificate PKCS12, CER, or CRT
Service Certificate/Key PEM
Client Certificate (if needed) PEM

Example Certificates for IPsec, L2TP, and iOS Clients

If you encounter any problems with your certificates, compare your settings to those of the example certificates. Make sure to verify the X509 Basic Constraints and X509v3 Key Usage settings.

 Root Certificate  

Tab Setting Value
Status Signature Algorithm sha1WithRSAEncryption
Subject RFC 2253 emailAddress=support@barracuda.com,OU=documentation,O=Barracuda Networks,L=Innsbruck,ST=Tirol,C=AT
Hash 7b6d2374
Extensions X509v3 Basic Constraints CA:TRUE
X509v3 Key Usage Digital Signature, Key Agreement, Certificate Sign

Server Certificate  

Tab Setting Value
Status Signature Algorithm sha1WithRSAEncryption
Subject RFC 2253

emailAddress=support@barracuda.com,OU=docu,O=Barracuda Network AG,L=Innsbruck,ST=Tyrol,C=AT

Hash cc0460b5
Issuer RFC 2253

emailAddress=support@barracuda.com,OU=documentation,O=Barracuda Networks,L=Innsbruck,ST=Tirol,C=AT

Hash 7b6d2374
Extensions X509v3 Key Usage

Digital Signature, Key Agreement, Certificate Sign

X509v3 Subject Alternative Name DNS:vpnserver.yourdomain.com

Client Certificate

Tab Setting Values
Status Signature Algorithm sha1WithRSAEncryption
Subject RFC 2253

emailAddress=support@barracuda.com,OU=documentation,O=Barracuda Networks,L=Innsbruck,ST=Tyrol,C=AT

Hash c2b06d20
Issuer RFC 2253

emailAddress=support@barracuda.com,OU=documentation,O=Barracuda Networks,L=Innsbruck,ST=Tirol,C=AT

Hash 7b6d2374
Extensions X509v3 Key Usage

Digital Signature

Supported Encryption Algorithms

The firewall supports the following encryption algorithms for TINA, IPsec, and L2TP/IPsec VPN connections:

Algorithm Description
AES256 Advanced Encryption Standard with 256-bit encryption.
AES Advanced Encryption Standard with 128-bit encryption. AES is often chosen because it provides a good performance and security ratio.
3DES Triple DES. This algorithm is considered most secure but results in high system loads and lower VPN performance.
Blowfish A keyed, symmetric block cipher developed to replace DES.
CAST A 128-bit block cipher.
DES

Digital Encryption Standard. DES is the only export-restricted algorithm available.

DES is not recommended because it is considered unsafe.

NULL No encryption.

TINA Transport Protocols

For TINA VPNs, the following transport types are available:

Transport Protocol Description
UDP Stateless protocol that is best used for response-optimized tunnels. UDP is not recommended for unstable Internet connections.
TCP Stateful protocol that is used if the tunnel runs over a proxy server. Higher protocol overhead limits the response time. TCP is preferred for unstable Internet connections.
UDP & TCP Hybrid mode that creates two transport tunnels. To compensate for the weakness of both protocols, UDP is used for TCP connections, and TCP is used for stateless connections.
ESP The tunnel uses ESP (IP protocol 50). ESP is best for performance-optimized tunnels, but it does not work if NAT routers must be traversed.

IPv6 Support

s_to_s_IPv6_IPv4_VPN.png

The VPN service supports IPv6 for the VPN envelope. This means that the site-to-site and client-to-site VPN tunnels can be created between two IPv6 endpoints, but only IPv4 traffic can be sent through the tunnel. IPv6 is not supported for:

  • Dynamic Mesh
  • L2TP
  • PPTP
  • SSL VPN

VPN Routing Tables

You can configure how the VPN routes are introduced into the firewall's routing table.

  • Separate Routing Table – By default, the firewall uses source-based routing and creates separate premain routing tables for every VPN tunnel.
  • Single Routing Table – All VPN routes are inserted into the main routing table. VPN routes are inserted with a preference of 10.
Handling of Duplicate Routes
  • When a duplicate route to an existing VPN route in the main routing table is announced to the firewall via RIP, OSPF, or BGP, a duplicate routing entry is created and the route that was added last is used.
  • Creating a direct or gateway route with the same metric and destination as a VPN route in the main routing table results in duplicate routes. The route added last is used.
Enable the Single Routing Table for VPN Routes

Replacing policy-based routing by a single routing table without a proper migration plan may break your current setup and cause loss of connectivity.

  1. Go to VPN-Settings.
  2. Click in the URL edit field of your browser, move the cursor to the end of the line, and append &expert=1 to the URL string.
    vpn_main_routing_table_add_expert_mode.png
  3. Press Enter on your keyboard to confirm the change of the URL.
  4. The browser will reload the window VPN >  Settings with a section VPN Routes.

    If your session expired, you will be asked to log into the firewall again. Enter your credentials and click Sign in.
  5. Click Yes to enable VPN routing via the main routing table.
    single_routing_table_for_VPN_routes_ON.png
  6. In the VPN Interface IP Address field, enter a virtual server IP address that is also part of a published VPN network. E.g., 192.168.200.200 if one of the Local Networks of the VPN tunnel is 192.168.200.0/24.
    set_IP_for_single_routing_table_for_VPN_routes.png
  7. Click Save.

Local out traffic is now sent and received correctly through the site-to-site VPN tunnel.

Last updated on