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 Barracuda NextGen Firewall F-Series supports multiple encryption algorithms for VPN connections. For TINA VPNs, multiple transport types are also available.
Some data signed by the private key for verification.
Identity of the the CA.
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 runtime.
L2TP/IPsec VPN service certificates. For more information, see How to Configure a Client-to-Site L2TP/IPsec VPN.
Certificates for iOS devices used as a VPN client. For more information, see How to Set Up External CA VPN Certificates.
A full-featured public key infrastructure (PKI) for self-signed certificates, is included with the Barracuda NextGen Control Center (C610,VC610, or VC820).
Use an external CA (PKI) for firewalls that are standalone or managed with a Barracuda NextGen Control Center C400 or VC400.
If you encounter any problems with your certificates, compare your settings to those of the example certificates. Especially verify the X509 Basic Constraints and X509v3 Key Usage settings.
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.
Digital Encryption Standard. DES is the only export restricted algorithm available.
DES is not recommended because it is considered unsafe.
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.
You can configure how the VPN routes are introduced into the firewall's routing table.
Separate Routing Table – By default, the NextGen Firewall F-Series 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.
When a duplicate route to an existing VPN route in the main routing table is announced to the NextGen Firewall F-Series 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.
Replacing policy-based routing by a single routing table without a proper migration plan may break your current setup and cause loss of connectivity.
Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > VPN > VPN Settings.
Click Click here for Server Settings. Set Add VPN Routes to Main Routing Table (Single Routing Table) to Yes.
To send the local out traffic through the VPN tunnel, you must configure an IP address from the source network for the VPN interface.
In the Settings tab, click the Click here for Server Settings link. The Server Settings window opens.
In the Server Settings window, click the Advanced tab.
Next to the VPN Interface Configuration table, click Add.
In the VPN Interface Properties window, configure the following settings and then click OK.
In the IP Addresses 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.
Click OK. The interface is now listed in the VPN Interface Configuration table.
In the Server Settings window, click OK.
Local Out traffic is now sent and received correctly through the Site-to-Site VPN tunnel.