1. NET 536 Network Security Firewalls and VPN
Networks and Communication Department
Firewalls and VPN

2. Firewall Provides a barrier and/or filter between networks
Can be configured to block packets
Sometimes called a level 4 switch
Blocks access to network from certain applications and/or addresses by examining packets going throw it and deciding whether to forward them. Examines IP, TCP and UDP headers to determine specific IP addresses and/or specific applications (i.e. ports) to allow or block.
Level 4 switch because it looks at port numbers in the Transport Layer (Level 4 of the OCI).

3. VPN VPN (Virtual Private Network) Uses IP Tunneling.
Acts as a private network connection (inside a company for example) while running over a more public internet.
Uses IP Tunneling.

4. Advantages: Firewall and VPN
Firewalls
Provides protection to network resources by restricting access based upon information contained in packets
Common Use: Allows the separation of Intra-nets from the Internet
VPN
Allows access through firewalls by creating virtual circuits using tunneling.
Common Use: Provides secure remote access to an institution's protected resources

5. Tunneling Wraps an IP frame inside another frame of the same layer.
An IP frame inside another IP frame.
The inner packet can be encrypted, which allows for privacy of the connection.
You may remember IP6 was tested by tunneling inside IP4 packets.
Because of this, can be used to bypass the firewall, because the packet you are sending is no longer of the type being blocked.

6. Disadvantages: VPNs Tunneling increases the length of IP packets
May result in inefficient use of bandwidth, especially for short packets
Potential performance impact at end routers as they need to do more work
Remove headers, decrypt packet body‏
Administrative overhead and cost associated with managing the VPN server

7. Scenario 1- No Firewall

8. Scenario 1 - Described Simulates two sales people working offsite
Characterized by light Web Browsing and light Database access
Connect to a server via the Internet.

9. Scenario 2- Firewall

10. Scenario 2- Described
Replaces the simple router previously used to connect to the server with a firewall
Configured to block Database access.
The Sales people can still engage in Web Browsing

11. Scenario 3- Firewall with VPN

12. Scenario 3- Described Scenario 3 configures a VPN for Sales A
Sales A now tunnels through the firewall and can access the database
Still allowing web browsing
Sales B is restricted to web browsing with no database access.

13. Results
Average Client DB and Client HTTP Traffic for the three scenarios. Show live.

14. Exercise1
From the obtained graphs, explain the effect of the firewall, as well as the configured VPN, on the database traffic requested by Sales A and Sales B.

15. Answer 1 - Observations From the captured graphs, it can be observed
that without the firewall both Sales A and Sales B
clients were able to access the database, while
adding the firewall prevented both Sales clients
from accessing it. Configuring the VPN access for
Sales A allowed it to access the database through the firewall.

16. Exercise 2
2)Compare the graphs that show the received HTTP traffic with those that show the received database traffic.

17. Answer 2 - Observations Comparing the graphs of received HTTP and
database traffic for both Sales A and B clients
confirms that both clients receive HTTP traffic in all
scenarios (i.e., the firewall permits HTTP traffic from
both Sales clients). Once the firewall is in place
however, database traffic is only permitted through
the firewall using a VPN.

18. Exercise 3
3) Generate and analyze the graph(s) that show the effect of the firewall, as well as the configured VPN, on the response time (delay) of the HTTP pages and database queries.

19. Answer 3- DB Queries
Obviously there is no DB Query response times for the Firewall without VPN
Firewall with VPN response time is slower due to overhead from the VPN and additional router.