ewalls
- Second Generation-application-level firewall or proxy server
- Third Generation- Stateful inspection firewalls
- Fourth Generation-dynamic packet filtering firewall
- Fifth Generation- kernel proxy.
Question 95. Mention The Functions Of First Generation Firewall ?
Examines every incoming packet header and selectively filters packets based on address, packet type, port request, and others factors.
Question 96. What Are The Restrictions Of First Generation Firewall?
The restrictions most commonly implemented are based on:
- IP source and destination address
- Direction (inbound or outbound)
- TCP or UDP source and destination port-requests.
Question 97. What Is The Advantage Of Second Generation Firewalls?
The primary disadvantage of application-level firewalls is that they are designed for a specific protocol and cannot easily be reconfigured to protect against attacks on protocols for which they are not designed.
Question 98. Define Stateful Inspection Firewall ?
It keeps track of each network connection established between internal and external systems using a state table which tracks the state and context of each packet in the conversation by recording which station sent what packet and when.
Question 99. What Is The Disadvantage Of Third Generation Firewalls?
The primary disadvantage is the additional processing requirements of managing and verifying packets against the state table, which can possibly expose the system to a DoS attack. These firewalls can track connectionless packet traffic such as UDP and remote procedure calls (RPC) traffic.
Question 100. What Is The Function Of Fifth Generation Firewall?
The final form of firewall is the kernel proxy, a specialized form that works under the Windows NT Executive, which is the kernel of Windows NT. It evaluates packets at multiple layers of the protocol stack, by checking security in the kernel as data is passed up and down the stack.
Question 101. How Firewalls Are Categorized By Processing Mode?
The five processing modes are:
- Packet filtering
- Application gateways
- Circuit gateways
- MAC layer firewalls
Question 102. What Is The Drawback Of Packet-filtering Router?
The drawback of packet-filtering router includes a lack of auditing and strong authentication.
Question 103. What Are Screened-host Firewall Systems ?
Screened-Host firewall system allows the router to pre-screen packets to minimize the network traffic and load on the internal proxy.
Question 104. What Is The Use Of An Application Proxy?
An Application proxy examines an application layer protocol, such as HTTP, and performs the proxy services.
Question 105. What Are Dual Homed Host Firewalls?
The bastion-host contains two NICs (network interface cards)
One NIC is connected to the external network, and one is connected to the internal network
With two NICs all traffic must physically go through the firewall to move between the internal and external networks.
Question 106. What Is The Use Of Nat?
A technology known as network-address translation (NAT) is commonly implemented to map from real, valid, external IP addresses to ranges of internal IP addresses that are non-routable.
Question 107. What Are Screened-subnet Firewalls?
Consists of two or more internal bastion-hosts, behind a packet-filtering router, with each host protecting the trusted network
The first general model consists of two filtering routers, with one or more dual-homed bastion-host between them
The second general model involves the connection from the outside or untrusted network.
Question 108. What Are Sock Servers?
The SOCKS system is a proprietary circuit-level proxy server that places special SOCKS client-side agents on each workstation.
Question 109. What Are The Recommended Practices In Designing Firewalls?
- All traffic from the trusted network is allowed out
- The firewall device is always inaccessible directly from the public network
- Allow Simple Mail Transport Protocol (SMTP) data to pass through your firewall, but insure it is all routed to a well-configured SMTP gateway to filter and route messaging traffic sec