Networking TCP/IP Online Test, Networking Question and Answers

SMTP, HTTP and FTP use TCP.

The four layers of the TCP/IP stack (also called the DoD model) are Application/Process, Host-to-Host, Internet, and Network Access. The Host-to-Host layer is equivalent to the Transport layer of the OSI model.

A client that sends out a DHCP Discover message in order to receive an IP address sends out a broadcast at both layer 2 and layer 3. The layer 2 broadcast is all Fs in hex, or FF:FF:FF:FF:FF:FF. The layer 3 broadcast is 255.255.255.255, which means all networks and all hosts. DHCP is connectionless, which means it uses User Datagram Protocol (UDP) at the Transport layer, also called the Host-to-Host layer.

Dynamic Host Configuration Protocol (DHCP) is used to provide IP information to hosts on your network. DHCP can provide a lot of information, but the most common is IP address, subnet mask, default gateway, and DNS information.

Class A private address range is 10.0.0.0 through 10.255.255.255. Class B private address range is 172.16.0.0 through 172.31.255.255, and Class C private address range is 192.168.0.0 through 192.168.255.255.

Proxy ARP can help machines on a subnet reach remote subnets without configuring routing or a default gateway.

The four layers of the DoD model are Application/Process, Host-to-Host, Internet, and Network Access. The Internet layer is equivalent to the Network layer of the OSI model.

DHCP, SNMP, and TFTP use UDP.

A Class C network address has only 8 bits for defining hosts: 2⁸ – 2 = 254.

Both FTP and Telnet use TCP at the Transport layer; however, they both are Application layer protocols, so the Application layer is the best answer.

To turn a binary number into decimal, you just have to add the values of each bit that is a 1. The values of 10011101 are 128, 16, 8, 4, and 1. 128 + 16 + 8 + 4 + 1 = 157.

Hexadecimal is a base-16 number system. The values of hexadecimal are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F-16 characters total, from which to create all the numbers you’ll ever need. So, if 1001 in binary is 9, then the hexadecimal equivalent is 9. Since we then have 1101, which is 13 in binary, the hexadecimal answer is D and the complete hexadecimal answer is 0x9D.

Internet Control Message Protocol (ICMP) is used to send error messages through the network, but they do not work alone. Every segment or ICMP payload must be encapsulated within an IP datagram (or packet).

This seems like a hard question at first because it doesn’t make sense. The listed answers are from the OSI model and the question asked about the TCP/IP protocol stack (DoD model). However, let’s just look for what is wrong. First, the Session layer is not in the TCP/IP model; neither are the Data Link and Physical layers. This leaves us with the Transport layer (Host-to-Host in the DoD model), Internet layer (Network layer in the OSI), and Application layer (Application/Process in the DoD).

Although Telnet does use TCP and IP (TCP/IP), the question specifically asks about layer 4, and IP works at layer 3. Telnet uses TCP at layer 4.

ICMP is used for diagnostics and destination unreachable messages. ICMP is encapsulated within IP datagrams, and because it is used for diagnostics, it will provide hosts with information about network problems.

Telnet, File Transfer Protocol (FTP), and Trivial FTP (TFTP) are all Application layer protocols. IP is a Network layer protocol. Transmission Control Protocol (TCP) is a Transport layer protocol.

Address Resolution Protocol (ARP) is used to find the hardware address from a known IP address.

DNS uses TCP for zone exchanges between servers and UDP when a client is trying to resolve a hostname to an IP address.