Sample Answer

b) Application-level firewall acts as a host computer between the organization’s network and the Internet. Users who want to access the organization’s network must log in to the application-level firewall and can only access information that they are allowed. Advantages for using application-level firewall are: can set user access control as to what information can be accessed and what information cannot be accessed. The downside is that the user will have to remember additional passwords due to the extra security implemented by the firewall.

IV. Security Issues (Threats) for using a VPN

As any network VPN has its own security issues and threats. These issues must be carefully handled to ensure confidentiality and integrity of data and information along with the network security.
Some of the security risks involved are:
a) User Authentication: Where the VPN security is only as strong as the users authentication (passwords). Simple passwords may lead to hacking attacks and cracking the password will be easy. Certificates are generally given to enhance the security of the authentication.
b) Digital Certificates: Are based on public/private key pairs. Each certificate contains a private key that identifies its end receiver. The trusted Certificate Authority such as enterprise networks produces the private key. The sender can verify the receiver certificate using a machine public key to decrypt the message.
c) Infecting the network: If the company does not meet the security requirements it will be open for infection from the local area networks in the form of worms, viruses, trojans, bots etc. Having a good anti-virus which is up-to date is mandatory .
d) Tunnelling: Tunnelling is a key part of a VPN. It is responsible for encapsulating data packets inside a protocol from the start to the end of the network. Split tunnelling happens when a user on one end of a VPN tunnel simultaneously exchanges network traffic with another user on the other end of the tunnel with both public network and private network before all of the network traffic is inside the VPN tunnel. This provides an opportunity for hackers who are on the shared network to get illegal access to the host computer and use it to gain network access to the internal network of the organization. A host-based firewall is an effective way to defend against network-based attacks.
e) Domain Name Server Leakage (DNS Leakage): VPN ensures that the users data packets go through a private tunnel but on certain events there could be a DNS leakage where the network uses the users default DNS address instead of the DNS provided by the VPN.

V. Security Benefits of using a VPN
Virtual private networks offers a lot of benefits. The two most important benefits are cost savings and the network scalability. VPN allows easy maintenance. The cost for running a VPN network is cheap and helps reduce the company/business working costs. The various security benefits of VPN are discussed below.