SFT test 1

How many bits in a byte?

8

The maximum decimal value that can be represented in a byte is:

255

What is a MAC address?

the hardware address assigned to the network card/interface

What does the Address Resolution Protocol ARP do?

Resolves a known IP address with a MAC address

A server port of UDP or TCP 53 is typically associated with what service?

DNS

How does a host that sends TCP data to know that the data was received?

A TCP acknowledgement is sent from the receiver

Which of the following best characterizes TCP verses UDP (in most cases)?

TCP is slower, more reliable, and requires more overhead

Which of the following best characterizes ICMP?

It is used to communicate error conditions

A TCP flag of RESET indicates:

An intention to abort to TCP connection

TCP typically begins a session with:

The three-way handshake of the client to the server with SYN set the server response of SYN/ACK, and the client acknowledgement of ACK

A value of 6 in the protocol field of the IP header represents:

An embedded protocol of TCP follows the IP header

IP fragmentation occurs when:

When there are more bytes in the IP packet than the size of the Maximum Transmission Unit of all links from sender to receiver

Some of the fields in an IPv4 packet that are used by the receiver to reassemble associated fragments are:

The IP identification field identifies all associated fragments, the More Fragment bit to indicate whether or not more fragments follow the current one and the fragment offset to indicate where a particular fragment falls in relation to other fragments

The Time to Live (TTL) field/value found in the IP header is used to:

Expire IP packets in transit when the TTL value becomes 0

What is the purpose of the IP checksum?

To make sure that data in the IP header is not corrupted in transit

What is a common use of DNS?

Resolution of a host name to an IP address

What is a typical response from a host that receives a UDP packet on a non-listening port?

An ICMP port unreachable message to the sender

Suppose a SYN packet is spoofed using a real IP address and then sent to a server that responds with a SYN/ACK to the actual IP address. How does the real IP address respond?

With a reset since it did not send the SYN

What are some differences between IPv4 and IPV6?

The IPv6 addresses are 4 times larger, and some of the fields/functionality previously in the IPv4 header is now in IPv6 extension headers

Suppose you had a tool that allowed you to craft an ICMP echo request over Ethernet, but you needed to tell the tool how to compose the request layer by layer in the proper order. How would you order the different layers?

Ethernet header, followed by IP header, followed by ICMP header, followed by optional ICMP data.

What is the function of a router?

It attempts to move the IP packet one hop closer to the destination

The IP protocol field identifies:

To associate a chronological number with each TCP segment, allowing the receiver to properly reorder the individual segments of data

A function of the TCP sequence number is:

To associate a chronological number with each TCP segment, allowing the receiver to properly reorder the individual segments of data

Suppose you want to ping a new known IPv4 address on your network. What must happen first?

An ARP request must be issued by your host to discover the MAC address associated with the IP address

When an IPv4 packet traverses a router what are some of the tasks the router must perform?

Decrement the Time to Live value by 1 and recompute the IP checksum