Question

question 1) Give some advantages and disadvantages of :
a. Stateless Address Auto configuration in IPv6 (2.5 marks)
b. Stateful Address Auto configuration in IPv6 (2.5 marks)
question 2) . (a) What is the purpose of extension headers in IPv6? List the names of at least two extension headers used in IPv6. [2.5 Marks]
   (b) How are jumbograms used in the IPv6 environment? (2.5 marks)
question 3)  Compare and contrast the OSI reference model with the TCP/IP networking model. Which one do you think is more useful when working with and describing networks and why? [5 Marks]
question 4) In the context of securing TCP/IP environment, provide a brief discussion on typical TCP/IP attacks, exploits and break-ins [5 Marks]
question 5) Explain the three ways, route entries are placed in a routing table ?

Answer 1

question 1) Give some advantages and disadvantages of :

A) Stateless Address Auto configuration in IPv6 (2.5 marks)

Ans Advantages:

Advantages of stateless auto configuration are that there is almost no configuration for the client to do when the computer tries to gain an IP address. All the client needs to do is wait on the machine getting an IP address from the information gained from the router and that is all that is required to get up and running.

Another benefit of stateless auto configuration is that it does not need a DHCP server in order for hosts to gain IP addresses and even if it needs to get other information later on it can then contact a DHCP server to get other information such as DNS server addresses.

disadvantages

A disadvantage of this method is that it doesn't get the entire network configuration that it may need to be fully functional on the network. Instead it uses DHCPv6 when it has enough configuration to get reach the DHCPv6 server to get the rest of the configuration. This is not good as it would be more efficient to get all of the needed configuration by using stateless auto configuration.

b. Stateful Address Auto configuration in IPv6 (2.5 marks)

advantages

Stateful auto configuration is used when there is no router on the link that is advertising router advertisements to provide the information to give its self an IP address. Instead it goes to a DHCP server that issues the host with all of the required configuration to get access to the network.\

disadvantages

A disadvantage of stateful auto configuration is that it needs a DHCPv6 server in order to get an IP address and if the DHCPv6 server goes down then there is no way for hosts to get network configurations unless there is a router on the link that is advertising router advertisements. But in the worst case scenario when their being no router available then there is no way for hosts to get assigned an IP address.

question 2) . (a) What is the purpose of extension headers in IPv6?

Ans:

IPv6 extension headers contain supplementary information used by network devices (such as routers, switches, and endpoint hosts) to decide how to direct or process an IPv6 packet. The length of each extension header is an integer multiple of 8 octets. This allows subsequent extension headers to use 8-octet structures.

List the names of at least two extension headers used in IPv6. [2.5 Marks]

Ans:

1. Hop-by-Hop Options : Specifies delivery parameters at each hop on the path to the destination host.

Note: A hop-by-hop option can appear only following the IPv6 basic header. If it is used, it should be the first extension header. It cannot appear after another extension header.

2. Destination Options : Specifies packet delivery parameters for either intermediate destination devices or the final destination host. When a packet uses this header, the Next Header value of the previous header must be 60.

question 3)  Compare and contrast the OSI reference model with the TCP/IP networking model.

Ans:

OSI Model:

1. OSI is a generic, protocol independent standard, acting as a communication gateway between the network and end user.
2. In OSI model the transport layer guarantees the delivery of packets.
3. Follows vertical approach.
4. OSI model has a separate Presentation layer and Session layer.
5. Transport Layer is Connection Oriented.
6. Network Layer is both Connection Oriented and Connection less.
7. OSI is a reference model around which the networks are built. Generally it is used as a guidance tool.
8. Network layer of OSI model provides both connection oriented and connectionless service.
9. Protocols are hidden in OSI model and are easily replaced as the technology changes.
10. It is protocol independent.
11. It has 7 layers

TCP/IP Model:

1. TCP/IP model is based on standard protocols around which the Internet has developed. It is a communication protocol, which allows connection of hosts over a network.
2. In TCP/IP model the transport layer does not guarantees delivery of packets. Still the TCP/IP model is more reliable.
3. Follows horizontal approach.
4. TCP/IP does not have a separate Presentation layer or Session layer.
5. Transport Layer is both Connection Oriented and Connection less.
6. Network Layer is Connection less.
7. TCP/IP model is, in a way implementation of the OSI model.
8. The Network layer in TCP/IP model provides connectionless service.
9. In TCP/IP replacing protocol is not easy.
10. It is also protocol dependent.
11. It has 4 layers

question 4) In the context of securing TCP/IP environment, provide a brief discussion on typical TCP/IP attacks, exploits and break-ins [5 Marks]

Ans:

Successful attacks against TCP/IP networks and services rely on two powerful weapons:Profiling, foot printing tools and working knowledge of the weaknesses or implementation process(i.e., bugs) that permit unauthorized access

Important terms in TCP/IP attacks:

An attack is an attempt to obtain access to information, to damage or destroy such information, or to otherwise compromise system security or usability, preferably without detection until the deed has been done.

An exploit reveals a system vulnerability and is often documented, either by the manufacturer or by an attacker.

A break-in is a successful attempt to compromise a system's security.

A threat is any activity that represents a potential danger or attacks on a system or network.
A vulnerability is any protocol, service or system facility known to be susceptible to attack.

Ip related attacks:

DOS attacks: In a DOS attack, a service is inundated with request, or malformed service requests, which cause a server to hang or freeze, preventing it from responding to input.
Man in the middle attacks- here the attacker is able to intercept traffic from both parties to a communication and either pass the traffic unaltered to the other end of the communication link or forge a reply from either side.
Ip service attacks- Numerous Ip services are subject to attacks are called Ip service attacks. Often these occur through the TCP service's well known ports.
IP service implementation vulnerabilities- Sometimes, hackers discover bugs in specific implementations of IP services on particular platforms that can be exploited to permit normally illega; operations to occur on machines where those services are available.
Insecure IP protocols and services- Some protocols, such as FTP and Telnet, can require user account names and passwords to permit access to their services. But these protocals do not encrpt that data, if malefactors sniff TP packets between senders and receivers while this information is visible, they can obtain valid account name and password pairs with which to break into a system.

question 5) Explain the three ways, route entries are placed in a routing table ?

Ans:

Routing table entries can be

1.default

2.manual

3.dynamic.

The default values are created when the TCP/IP stack is initialized.

Manual entries can be placed in the table for specific routes that may be desired. Some organizations, for instance, want specific traffic to go through specific routers. In that case, those routes can be entered into the routing table manually.

Routes can be added dynamically if the router supports dynamic routing tables.