Updating the anti-virus software regularly is the best way of protecting important data against virus attack.

Border Gateway Protocol (BGP) is an exterior gateway protocol. It communicates using a Transmission Control Protocol (TCP) and sends the updated router table information. The best path is chosen on the basis of cost metric associated with the route. It is used between gateway hosts in a network. Answer option C is incorrect. Open Shortest Path First (OSPF) is a routing protocol that is used in large networks. Internet Engineering Task Force (IETF) designates OSPF as one of the Interior Gateway Protocols. A host uses OSPF to obtain a change in the routing table and to immediately multicast updated information to all the other hosts in the network. Answer option A is incorrect. IGMP stands for Internet Group Management Protocol. IGMP is a communication protocol that is used to manage the membership of Internet protocol multicast groups. It is an integral part of the IP multicast specification. Although it does not actually act as a transport protocol, it operates above the network layer. It is analogous to ICMP for unicast connections. It is susceptible to some attacks, so firewalls commonly allow the user to disable it if not needed. Answer option B is incorrect. ICMP Router Discovery Protocol (IRDP) uses Internet Control Message Protocol (ICMP) router advertisements and router solicitation messages to allow a host to discover the addresses of operational routers on the subnet.It basically consists of 2 message types used for discovering local routers. The message type 9 is sent periodically or on request (using a message of type 10) to the local subnet from the local routers to propagate themselves. On boot, the client may send an ICMP message of type 10 to ask for local routers. When a client receives a message type 9, they add the router to their local routing-table.

Explanation
Explanation:
RG-59 type of coaxial cable is used for cable TV and cable modems.
Answer option A is incorrect. RG-8 coaxial cable is primarily used as a backbone in an Ethernet LAN
environment and often connects one wiring closet to another. It is also known as 10Base5 or ThickNet.
Answer option B is incorrect. RG-62 coaxial cable is used for ARCNET and automotive radio antennas.
Answer option D is incorrect. RG-58 coaxial cable is used for Ethernet networks. It uses baseband signaling
and 50-Ohm terminator. It is also known as 10Base2 or ThinNet.

A birthday attack is a class of brute force attacks that exploits the mathematics behind the birthday problem in probability theory. It is a type of cryptography attack. The birthday attack depends on the higher likelihood of collisions found between random attack attempts and a fixed degree of permutations.
Answer option D is incorrect. A dictionary attack is a technique for defeating a cipher or authentication mechanism by trying to determine its decryption key or passphrase by searching likely possibilities. A dictionary attack uses a brute-force technique of successively trying all the words in an exhaustive list (from a pre- arranged list of values). In contrast with a normal brute force attack, where a large proportion key space is searched systematically, a dictionary attack tries only those possibilities which are most likely to succeed, typically derived from a list of words in a dictionary. Generally, dictionary attacks succeed because many people have a tendency to choose passwords which are short (7 characters or fewer), single words found in dictionaries, or simple, easily-predicted variations on words, such as appending a digit.
Answer option A is incorrect. Phishing is a type of internet fraud attempted by hackers. Hackers try to log into system by masquerading as a trustworthy entity and acquire sensitive information, such as, username, password, bank account details, credit card details, etc. After collecting this information, hackers try to use this information for their gain.
Answer option B is incorrect. A replay attack is a form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed. This is carried out either by the originator or by an adversary who intercepts the data and retransmits it, possibly as part of a masquerade attack by IP packet substitution.

Integrated Services Digital Network (ISDN) is a digital telephone/telecommunication network that carries voice, data, and video over an existing telephone network infrastructure. It requires an ISDN modem at both the ends of a transmission. ISDN is designed to provide a single interface for hooking up a telephone, fax machine, computer, etc. ISDN has two levels of service, i.e., Basic Rate Interface (BRI) and Primary Rate Interface (PRI). Answer option A is incorrect. The Point-to-Point Protocol, or PPP, is a data link protocol commonly used to establish a direct connection between two networking nodes. It can provide connection authentication, transmission encryption privacy, and compression. PPP is commonly used as a data link layer protocol for connection over synchronous and asynchronous circuits, where it has largely superseded the older, non-standard Serial Line Internet Protocol (SLIP) and telephone company mandated standards (such as Link Access Protocol, Balanced (LAPB) in the X.25 protocol suite). PPP was designed to work with numerous network layer protocols, including Internet Protocol (IP), Novell's Internetwork Packet Exchange (IPX), NBF, and AppleTalk. Answer option D is incorrect. The X.25 protocol, adopted as a standard by the Consultative Committee for International Telegraph and Telephone (CCITT), is a commonly-used network protocol. The X.25 protocol allows computers on different public networks (such as CompuServe, Tymnet, or a TCP/IP network) to communicate through an intermediary computer at the network layer level. X.25's protocols correspond closely to the data-link and physical-layer protocols defined in the Open Systems Interconnection (OSI) communication model. Answer option B is incorrect. Frame relay is a telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between end-points in a wide area network (WAN). Frame relay puts data in a variable-size unit called a frame. It checks for lesser errors as compared to other traditional forms of packet switching and hence speeds up data transmission. When an error is detected in a frame, it is simply dropped. The end points are responsible for detecting and retransmitting dropped frames.