Interview Questions with Answers for CCNA Level Jobs
Q. What is a router?
A. A router is a device that connects more than one physical network, or segments of a network, using IP routing software. As packets reach the router, the router reads them and forwards them to their destination.
Q. Discuss wireless networking.
A. This is a network configured to use communication techniques such as infrared, cellular, or microwave, so that cable connections are not required.
Q. Discuss WAN (wide area network).
A. A WAN is extended over longer distances that a LAN (local area network). It can range from a few miles to across the world. TCP/IP is the primary WAN protocol and was developed to provide reliable, secure data transmissions over long distances.
Q. What is OSPF?
A. Open Shortest Path First is a routing protocol that supports the concept of a core area to which everything attaches.
Q. What is BGP?
A. Border Gateway Protocol is used for routing between networks on the Internet core, and it supports many advanced routing features.
Q. What is an autonomous system?
A. An autonomous system is a community of interest. Used in conjunction with routing protocols, it breaks up parts of the network into manageable chunks.
Q. What is dial on demand?
A. Dial on demand is a technology that only activates network connection when “interesting” packets are to be sent across the infrastructure.
Q. What mask would you use to supernet two class C addresses?
A. The subnet would be 255.255.254.0.
Q. What is VLANing?
A. Virtual LAN is used on large LANs to break up the network into smaller broadcast domains. This creates communities of interest. These communities can be based around organizational structures.
Q. What is CIDR?
A. Classless Internet domain routing is used in conjunction with classless routing protocols to summarize the Internet into smaller routing tables.
Q. What is VLSM?
A. Variable Length Subnet Mask is used to allocate the amount of address space required by the end network.
Q. What is a class D IP address?
A. Class D addresses are multicast addresses.
Q. What addresses do multicasts start with?
A. Multicasts start with the address 18.104.22.168.
Q. Which name resolution system is implemented with TCP/IP by default?
A. Although WINS is a name resolution that is implemented by TCP/IP by default, it only works on Windows-based networks. The only true name resolution system that almost every TCP/IP networks uses is DNS.
Q. You are the administrator of a 100-station Ethernet network. Your users are complaining of slow network speeds. What could you replace your hub with to increase your network throughput?
A. A switch would increase performance by making virtual, direct connections between sender and receiver. A bridge and router would actually decrease performance because these devices introduce latency into the communication.
Q. Which TCP/IP utility is most often used to test whether an IP host is up and functional?
A. The Ping utility is the most often used TCP/IP utility because it allows you to test individual hosts.
Q. Which utility can you use to find the MAC and TCP/IP address of your Windows NT or 2000 workstation?
A. The ipconfig utility is available for both these operating systems. It displays information like the MAC and TCP/IP address of your workstation as well as other TCP/IP configuration information.
Q. Which utility can you use to verify a packet’s path?
A. The tracert utility traces the route from the source IP host to the destination host.
Q. Which WAN technology uses digital signaling from sender to receiver?
A. The T-series of WAN connection (such as T1, T3, and so on) uses digital signaling from sending hardware to receiving hardware.
Q. Which remote access protocol can run over both serial and parallel connections?
A. Because PPP doesn’t contain a physical layer specification as part of the protocol, it can run over any kind of medium.
Q. What Microsoft TCP/IP protocol can be used over the Internet to create a secure, virtual network?
A. The Point-to-Point Tunneling Protocol (PPTP) allows you to create a secure, virtual connection between two points by tunneling one protocol inside another. Usually, a PPP connection is opened over a TCP/IP link.
Q. Which type of firewall checks for a current communication and the next packet needed?
A. A proxy provides firewall services by keeping track of all communications sessions and “prefetching” the next packets.
Q. Which type of security uses a file that identifies predefined IP addresses that are allowed to send data through a router?
A. Access Control List security uses a file (the ACL) that identifies which addresses can send data through a particular firewall or router.