Protocols

Question 1

HyperText Transfer Protocol (HTTP)

Answer 1

HTTP is used by Web browsers and Web servers to exchange files (such as Web pages) through the World Wide Web and intranets. HTTP can be described as an information requesting and responding protocol. It is typically used to request and send Web documents, but is also used as the protocol for communication between agents using different TCP/IP protocols.

Question 2

HTTP over SSL (HTTPS)

Answer 2

HTTPS is a secure form of HTTP that uses SSL to encrypt data before it is transmitted.

Question 3

Secure Sockets Layer (SSL)

Answer 3

SSL secures messages being transmitted on the Internet. It uses RSA for authentication and encryption. Web browsers use SSL (Secure Sockets Layer) to ensure safe Web transactions. URLs that begin with https:// trigger your Web browser to use SSL.

Question 4

Transport Layer Security (TLS)

Answer 4

TLS ensures that messages being transmitted on the Internet are private and tamper proof. TLS is implemented through two protocols: TLS Record–Can provide connection security with encryption (with DES for example), TLS Handshake–Provides mutual authentication and choice of encryption method.

Question 5

File Transfer Protocol (FTP)

Answer 5

FTP provides a generic method of transferring files. It can include file security through usernames and passwords, and it allows file transfer between dissimilar computer systems. FTP can transfer both binary and text files, including HTML, to another host. FTP URLs are preceded by ftp:// followed by the DNS name of the FTP server. To log in to an FTP server, use: ftp://username@servername.

Question 6

Trivial File Transfer Protocol (TFTP)

Answer 6

TFTP is similar to FTP. It lets you transfer files between a host and an FTP server. However, it provides no user authentication and no error detection. TFTP is often used when transferring files such as video, audio, or images. Because it does not perform error detection, TFTP is faster than FTP, but might be subject to file errors.

Question 7

Secure File Transfer Protocol (SFTP)

Answer 7

SFTP is a file transfer protocol that uses Secure Shell (SSH) to secure data transfers. SSH ensures that SFTP transmissions use encrypted commands and data which prevent data from being transmitted over the network in clear text.

Question 8

Secure Copy (SCP)

Answer 8

SCP is associated with Unix/Linux networks and used to transfer files between systems. Like SFTP, SCP relies on SSH to ensure that data and passwords are not transmitted over the network in clear text.

Question 9

Simple Mail Transfer Protocol (SMTP)

Answer 9

SMTP is used to route electronic mail through the internetwork. SMTP is used: Between mail servers for sending and relaying mail, By all e-mail clients to send mail, receiving mail from an Exchange server.

Question 10

Post Office Protocol 3 (POP3)

Answer 10

POP3 is part of the TCP/IP protocol suite and is used to retrieve e-mail from a remote server to a local client over a TCP/IP connection. With POP3, e-mail messages are downloaded to the client.

Question 11

Internet Message Access Protocol 4 (IMAP4)

Answer 11

IMAP4 is an e-mail retrieval protocol designed to enable users to access their e-mail from various locations without the need to transfer messages or files back and forth between computers. Messages remain on the remote mail server and are not automatically downloaded to a client system.

Question 12

Dynamic Host Configuration Protocol (DHCP)

Answer 12

DHCP is a method for automatically assigning addresses and other configuration parameters to network hosts. Using a DHCP server, hosts receive configuration information at startup, reducing the amount of manual configuration required on each host.

Question 13

Domain Name System (DNS)

Answer 13

DNS is a system that is distributed throughout the internetwork to provide address/name resolution. For example, the name www.mydomain.com would be identified with a specific IP address.

Question 14

Network Time Protocol (NTP)

Answer 14

NTP is used to communicate time synchronization information between systems on a network.

Question 15

Lightweight Directory Access Protocol (LDAP)

Answer 15

LDAP is used to allow searching and updating of a directory service. The LDAP directory service follows a client/server model. One or more LDAP servers contain the directory data, the LDAP client connects to an LDAP Server to make a directory service request.

Question 16

Simple Network Management Protocol (SNMP)

Answer 16

SNMP is a protocol designed for managing complex networks. SNMP lets network hosts exchange configuration and status information. This information can be gathered by management software and used to monitor and manage the network.

Question 17

Remote Terminal Emulation (Telnet)

Answer 17

Telnet allows an attached computer to act as a dumb terminal, with data processing taking place on the TCP/IP host computer. It is still widely used to provide connectivity between dissimilar systems. Telnet can also be used to test a service by the use of HTTP commands.

Question 18

Secure Shell (SSH)

Answer 18

SSH allows for secure interactive control of remote systems. SSH uses RSA public key cryptography for both connection and authentication. SSH uses the IDEA algorithm for encryption by default, but is able to use Blowfish and DES. SSH is a secure and acceptable alternative to Telnet.

Question 19

Transmission Control Protocol (TCP)

Answer 19

TCP provides services that ensure accurate and timely delivery of network communications between two hosts. TCP provides the following services to ensure message delivery: Sequencing of data packets, Flow control, andErr or checking

Question 20

User Datagram Protocol (UDP)

Answer 20

UDP is a host-to-host protocol like TCP. However, it does not include mechanisms for ensuring timely and accurate delivery. Because it has less overhead, it offers fast communications, but at the expense of possible errors or data loss.

Question 21

ICMP

Answer 21

ICMP works closely with IP in providing error and control information, by allowing hosts to exchange packet status information, which helps move the packets through the internetwork. Two common management utilities, ping and traceroute, use ICMP messages to check network connectivity. ICMP also works with IP to send notices when destinations are unreachable, when devices’ buffers overflow, the route and hops packets take through the network, and whether devices can communicate across the network.

Question 22

Internet Group Membership Protocol (IGMP)

Answer 22

IGMP is a protocol for defining host groups. All group members can receive broadcast messages intended for the group (called multicasts). Multicast groups can be composed of devices within the same network or across networks (connected with a router).