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Computer Networks & Cisco Questions

Page 3 of 6 (Displaying Questions 201 – 300 of 542 Total)

201. What is the main purpose of an IP address?

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An IP address is like a unique phone number for your device on the network, allowing it to be located and communicate with other devices.

Added: Dec 01, 2025

202. What is the primary difference between IPv4 and IPv6?

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IPv4 uses 32 bits and is running out of addresses. IPv6 uses 128 bits and provides a massive, nearly unlimited number of addresses.

Added: Dec 01, 2025

203. How is an IPv4 address typically written or formatted?

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It is written as four numbers separated by dots (periods), such as 192.168.1.1.

Added: Dec 01, 2025

204. What is a Public IP Address?

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A public IP address is the single unique address assigned to your entire network by your ISP (Internet Service Provider). It is used to communicate with the rest of the Internet.

Added: Dec 01, 2025

205. What is a Private IP Address?

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A private IP address is used to identify devices only within your local network (like your home or office). It cannot be used directly on the public Internet.

Added: Dec 01, 2025

206. Why do we need Private IP addresses?

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They allow every device in a large private network to have a unique address without using up the limited pool of public IP addresses.

Added: Dec 01, 2025

207. What common tool is used by a router to let many devices with private IPs share one public IP?

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Network Address Translation (NAT) is the common tool used by the router for this purpose.

Added: Dec 01, 2025

208. What is the most common Private IP range used in homes and small businesses?

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The most common private range starts with 192.168 (e.g., 192.168.1.x).

Added: Dec 01, 2025

209. Name the three main ranges of Private IP addresses in IPv4.

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The three ranges start with 10.0.0.0, 172.16.0.0, and 192.168.0.0.

Added: Dec 01, 2025

210. If you visit a website, will the server see your Private IP address or your Public IP address?

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The server will only see your Public IP address, as the Private IP is hidden behind your router using NAT.

Added: Dec 01, 2025

211. What does the first number of an IPv4 address (like 10 in 10.1.1.1) help determine?

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It helps determine the IP address Class (A, B, C, D, or E) and the default size of the network.

Added: Dec 01, 2025

212. Which IP Class is typically used for very large networks with many devices, starting from 1 to 126?

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Class A is used for very large networks.

Added: Dec 01, 2025

213. Which IP Class is generally used for medium-sized networks, starting from 128 to 191?

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Class B is generally used for medium-sized networks.

Added: Dec 01, 2025

214. Which IP Class is most common for small networks like homes and small offices, starting from 192 to 223?

Show Answer

Class C is most common for small networks.

Added: Dec 01, 2025

215. What is the special IP address 255.255.255.255 used for?

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It is the network-wide broadcast address, used to send a message to all devices on the current network segment.

Added: Dec 01, 2025

216. What is a Subnet Mask used for, in relation to an IP address?

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The subnet mask helps a computer figure out which part of an IP address refers to the network and which part refers to the specific device (host).

Added: Dec 01, 2025

217. What is the default Subnet Mask for a Class C network?

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The default subnet mask is 255.255.255.0.

Added: Dec 01, 2025

218. What does CIDR (Classless Inter-Domain Routing) do?

Show Answer

CIDR is a modern way of allocating IP addresses and routing data that is more flexible than the old class system (A, B, C).

Added: Dec 01, 2025

219. What does the slash notation (e.g., /24) after an IP address represent in CIDR?

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The number after the slash tells you how many bits of the IP address are used for the network part (the network mask).

Added: Dec 01, 2025

220. What is the special IP address range 169.254.0.0 /16 used for?

Show Answer

This is the APIPA (Automatic Private IP Addressing) range. It is used when a device cannot find a DHCP server to get a real IP address.

Added: Dec 01, 2025

221. What is a Loopback Address (127.0.0.1) used for?

Show Answer

It is used by a device to talk to itself. It is mainly used by programmers or technicians to test if network software on the computer is working correctly.

Added: Dec 01, 2025

222. In IPv6, what is the equivalent of the Loopback Address (127.0.0.1 in IPv4)?

Show Answer

The IPv6 loopback address is ::1.

Added: Dec 01, 2025

223. How can you identify a Multicast IP address range in IPv4?

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Multicast addresses are in the Class D range, starting from 224.0.0.0 to 239.255.255.255.

Added: Dec 01, 2025

224. What is the difference between an IP address and a MAC address?

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An IP address is a logical address that can change and is used for routing across networks. A MAC address is a permanent physical address used only within a local network.

Added: Dec 01, 2025

225. How many octets (groups of numbers) are in an IPv4 address?

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There are four octets.

Added: Dec 01, 2025

226. What is the highest possible number in a single octet of an IPv4 address?

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The highest possible number is 255.

Added: Dec 01, 2025

227. What is the general term for the process of dividing a large network into smaller networks?

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This process is called Subnetting.

Added: Dec 01, 2025

228. What is the primary reason for using Subnetting?

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The primary reason is to improve network organization, manage traffic (reduce broadcast traffic), and enhance security.

Added: Dec 01, 2025

229. In a subnetted network, what is the Network ID (or Network Address)?

Show Answer

The Network ID is the first address in a network or subnet. It is used to identify the entire network and cannot be assigned to a device.

Added: Dec 01, 2025

230. In a subnetted network, what is the Broadcast ID (or Broadcast Address)?

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The Broadcast ID is the last address in a network or subnet. It is used to send a message to all devices in that specific subnet.

Added: Dec 01, 2025

231. What does the term "stateless" mean in the context of network protocols?

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It means that the protocol treats each request as new and independent, without remembering any previous requests or maintaining an ongoing session history.

Added: Dec 01, 2025

232. What is a typical example of a stateless protocol?

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HTTP (Hypertext Transfer Protocol) is a typical example of a stateless protocol.

Added: Dec 01, 2025

233. What does the term "stateful" mean in the context of network protocols?

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It means that the protocol remembers the previous steps in a conversation, maintaining an ongoing connection or session state, often for reliability.

Added: Dec 01, 2025

234. What is a typical example of a stateful protocol?

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TCP (Transmission Control Protocol) is a typical example of a stateful protocol.

Added: Dec 01, 2025

235. What is a "Socket" in networking?

Show Answer

A socket is a combination of an IP address and a port number. It uniquely identifies a specific program running on a specific device on the network.

Added: Dec 01, 2025

236. What is the hexadecimal (base 16) system and why is it used to represent IPv6 addresses?

Show Answer

Hexadecimal uses 16 symbols (0-9 and A-F). It is used because IPv6 addresses are very long, and hexadecimal makes them shorter and easier for people to read.

Added: Dec 01, 2025

237. What is the role of the Link-Local Address in IPv6 (starting with FE80)?

Show Answer

It is an address that automatically configures itself and is only used for communication with other devices on the same local link (segment), like APIPA in IPv4.

Added: Dec 01, 2025

238. What is the IPv6 address format that replaces the need for a DHCP server?

Show Answer

This format is called SLAAC (Stateless Address Autoconfiguration).

Added: Dec 01, 2025

239. What is the benefit of having a large number of available IP addresses with IPv6?

Show Answer

It allows every device, including many smart devices and sensors, to have a public, routable IP address, simplifying networking and removing the need for NAT.

Added: Dec 01, 2025

240. What is the term for hiding consecutive zeros in an IPv6 address (e.g., changing 2001:0db8:0000:0000::1)?

Show Answer

This is called "compression" or "zero compression".

Added: Dec 01, 2025

241. What is a reserved IP address?

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A reserved IP address is one that is specifically set aside for certain network functions, like the Network ID, Broadcast ID, or private addressing ranges, and cannot be used for a normal device.

Added: Dec 01, 2025

242. What is the main task of the DHCP server?

Show Answer

To automatically give out IP addresses and other necessary settings (like subnet mask and default gateway) to devices on the network.

Added: Dec 01, 2025

243. If a computer cannot get an IP address from DHCP, what temporary IP range will it use?

Show Answer

It will use the APIPA range (169.254.x.x).

Added: Dec 01, 2025

244. What is the standard port number for DNS (Domain Name System) lookups?

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The standard port for DNS is 53.

Added: Dec 01, 2025

245. What is the standard port number for the DHCP protocol?

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The standard ports for DHCP are 67 and 68 (UDP).

Added: Dec 01, 2025

246. What is the standard port number for FTP (File Transfer Protocol) data transfer?

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The standard port for FTP data transfer is 20.

Added: Dec 01, 2025

247. What is the standard port number for FTP control commands?

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The standard port for FTP control commands is 21.

Added: Dec 01, 2025

248. What is the key difference in connection quality between TCP and UDP?

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TCP provides reliable, ordered, and error-checked delivery. UDP provides fast, unreliable delivery with no error checking or order guarantee.

Added: Dec 01, 2025

249. When would you prefer to use UDP over TCP?

Show Answer

You prefer UDP for real-time applications like live video streaming, voice calls (VoIP), and online gaming, where speed is more important than retransmitting a lost packet.

Added: Dec 01, 2025

250. When would you prefer to use TCP over UDP?

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You prefer TCP for applications like web browsing (HTTP/HTTPS) and file transfers (FTP), where the data must arrive completely and in the correct order.

Added: Dec 01, 2025

251. What is the function of the sequence number in a TCP packet?

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The sequence number ensures that the data packets are reassembled in the correct order at the destination, even if they arrive out of sequence.

Added: Dec 01, 2025

252. What is the function of the acknowledgement number in a TCP packet?

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The acknowledgement number is used by the receiver to tell the sender which packet was successfully received and which one it is expecting next.

Added: Dec 01, 2025

253. What does the term "Well-Known Ports" refer to?

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These are port numbers from 0 to 1023 that are officially reserved and assigned to common network services like HTTP (80) and HTTPS (443).

Added: Dec 01, 2025

254. What does the term "Registered Ports" refer to?

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These are port numbers from 1024 to 49151 that are used by user applications or programs, but are not necessarily controlled by the operating system.

Added: Dec 01, 2025

255. What does the term "Dynamic or Private Ports" refer to?

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These are the highest range of port numbers (49152 to 65535) that are used temporarily by client programs to communicate with servers.

Added: Dec 01, 2025

256. What is a common use for the RDP (Remote Desktop Protocol)?

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RDP is used to allow a user to remotely access and control another computer over a network as if they were sitting in front of it.

Added: Dec 01, 2025

257. What is the standard port number for RDP (Remote Desktop Protocol)?

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The standard port for RDP is 3389.

Added: Dec 01, 2025

258. What is the purpose of the ARP Cache on a computer?

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The ARP Cache stores a temporary list of IP addresses and their corresponding MAC addresses of other devices on the local network that the computer has recently communicated with.

Added: Dec 01, 2025

259. What is the role of the DNS Resolver?

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The DNS Resolver is the first part of the DNS system (usually a service on your computer or router) that queries DNS servers to find the IP address of a requested domain name.

Added: Dec 01, 2025

260. What are the two main types of DNS queries?

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The two main types are Recursive queries (the resolver asks the server to find the answer for it) and Iterative queries (the server tells the resolver who to ask next).

Added: Dec 01, 2025

261. What is the difference between a "Host Name" and a "Domain Name"?

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A Host Name is the specific name of a computer (e.g., "web-server"). A Domain Name is the name of the website or network (e.g., "google.com").

Added: Dec 01, 2025

262. What is a "Record" in the context of DNS?

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A record is an entry in the DNS database that links a domain name to a specific piece of information, such as an IP address.

Added: Dec 01, 2025

263. What is the purpose of a DNS "A Record"?

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An A record (Address Record) is the most common type and links a domain name to an IPv4 address.

Added: Dec 01, 2025

264. What is the purpose of a DNS "AAAA Record"?

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An AAAA record links a domain name to an IPv6 address.

Added: Dec 01, 2025

265. What is the purpose of a DNS "CNAME Record"?

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A CNAME record (Canonical Name Record) creates an alias, or nickname, for another domain name.

Added: Dec 01, 2025

266. What is the purpose of a DNS "MX Record"?

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An MX record (Mail Exchanger Record) tells the network which server handles email for a specific domain name.

Added: Dec 01, 2025

267. What does the term "PDU" (Protocol Data Unit) mean at the Network Layer (Layer 3)?

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The PDU at the Network Layer is called a Packet.

Added: Dec 01, 2025

268. What does the term "PDU" (Protocol Data Unit) mean at the Data Link Layer (Layer 2)?

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The PDU at the Data Link Layer is called a Frame.

Added: Dec 01, 2025

269. What does the term "PDU" (Protocol Data Unit) mean at the Transport Layer (Layer 4)?

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The PDU at the Transport Layer is called a Segment (for TCP) or a Datagram (for UDP).

Added: Dec 01, 2025

270. What is the standard port for POP3 (Post Office Protocol version 3)?

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The standard port for POP3 is 110.

Added: Dec 01, 2025

271. What is the standard port for IMAP (Internet Message Access Protocol)?

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The standard port for IMAP is 143.

Added: Dec 01, 2025

272. At which OSI layer does a Repeater or Amplifier operate?

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It operates at the Physical Layer (Layer 1).

Added: Dec 01, 2025

273. At which OSI layer does a Switch operate?

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It primarily operates at the Data Link Layer (Layer 2).

Added: Dec 01, 2025

274. At which OSI layer does a Router operate?

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It primarily operates at the Network Layer (Layer 3).

Added: Dec 01, 2025

275. What information does a Layer 2 Switch use to make forwarding decisions?

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It uses the MAC (Media Access Control) addresses of the devices.

Added: Dec 01, 2025

276. What information does a Layer 3 Router use to make forwarding decisions?

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It uses the IP addresses of the destination networks.

Added: Dec 01, 2025

277. What is the difference between a Bridge and a Switch?

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A bridge typically connects two network segments and has only a few ports. A switch is a high-speed, multiport bridge.

Added: Dec 01, 2025

278. What is a "Next Hop" in routing?

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The next hop is the next router to which a packet should be sent in order to get closer to its final destination.

Added: Dec 01, 2025

279. What is the main function of the Presentation Layer (Layer 6)?

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It is responsible for data translation, encryption/decryption, and compression, ensuring that data is readable by the receiving application.

Added: Dec 01, 2025

280. What is the main function of the Session Layer (Layer 5)?

Show Answer

It establishes, manages, and terminates the communication sessions between applications on different devices.

Added: Dec 01, 2025

281. What is the key role of the Data Link Layer (Layer 2)?

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It handles error-free transfer of data frames between nodes on the same physical link and manages access to the physical network medium.

Added: Dec 01, 2025

282. What are the two main sublayers of the Data Link Layer (Layer 2)?

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They are the Logical Link Control (LLC) sublayer and the Media Access Control (MAC) sublayer.

Added: Dec 01, 2025

283. What is the purpose of the LLC (Logical Link Control) sublayer?

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The LLC sublayer manages communication between network software (Network Layer) and device hardware (MAC sublayer).

Added: Dec 01, 2025

284. What is the purpose of the MAC (Media Access Control) sublayer?

Show Answer

The MAC sublayer controls how a device on a network gains access to the data and permission to transmit it.

Added: Dec 01, 2025

285. What type of network topology is generally considered the most reliable due to multiple paths?

Show Answer

Mesh Topology is generally considered the most reliable.

Added: Dec 01, 2025

286. What is a drawback of the Star Topology?

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If the central device (hub or switch) fails, the entire network segment stops working.

Added: Dec 01, 2025

287. What is a drawback of the Bus Topology?

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If the central cable (backbone) breaks, the entire network fails, and troubleshooting is difficult.

Added: Dec 01, 2025

288. What is a "PoP" (Point of Presence) in networking?

Show Answer

A PoP is an access point or physical location where two or more networks or communication devices share a connection.

Added: Dec 01, 2025

289. What is a "Channel" in wireless networking?

Show Answer

A channel is a specific frequency band used to transmit and receive wireless signals. Different channels help avoid interference.

Added: Dec 01, 2025

290. What is "Throughput" in simple terms?

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Throughput is the actual, useful amount of data that successfully travels from one point to another in a given time, after all overhead and delays are considered.

Added: Dec 01, 2025

291. What is the main role of a Load Balancer?

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A load balancer is a device that spreads incoming network traffic across a group of backend servers to ensure no single server is overworked.

Added: Dec 01, 2025

292. What is the difference between a Layer 4 Load Balancer and a Layer 7 Load Balancer?

Show Answer

Layer 4 balancers use IP addresses and ports to distribute traffic. Layer 7 balancers use the actual content, like a URL or cookie, to decide where to send the traffic.

Added: Dec 01, 2025

293. What is the function of the Spanning Tree Protocol (STP)?

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STP is a network protocol that ensures there are no accidental loops in a network made of switches, which could otherwise cause a broadcast storm and bring down the network.

Added: Dec 01, 2025

294. What is a "Broadcast Storm"?

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A broadcast storm is a state where too many broadcast messages are sent at once and get trapped in a network loop, overwhelming the network and causing massive slowdowns.

Added: Dec 01, 2025

295. What is the purpose of the "Bridge Protocol Data Unit" (BPDU) in STP?

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BPDUs are special data frames sent between switches to share information and determine the best network topology and which paths to block to prevent loops.

Added: Dec 01, 2025

296. What is a "Managed Switch"?

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A managed switch is a switch that an administrator can access, configure, and monitor remotely, allowing for advanced features like VLANs and port control.

Added: Dec 01, 2025

297. What is an "Unmanaged Switch"?

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An unmanaged switch is a simple plug-and-play device that automatically forwards data with no configuration or remote control options.

Added: Dec 01, 2025

298. What are the two major categories of Routing Protocols?

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The two categories are Interior Gateway Protocols (IGP) which work inside a single network, and Exterior Gateway Protocols (EGP) which work between different networks.

Added: Dec 01, 2025

299. What is the most well-known Exterior Gateway Protocol (EGP)?

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The Border Gateway Protocol (BGP) is the most well-known EGP, used to route traffic across the Internet.

Added: Dec 01, 2025

300. What is the difference between a "Host" and a "Node" in networking?

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A host is any device with an IP address (like a computer or server). A node is any device that can participate in the network, including routers, switches, and hosts.

Added: Dec 01, 2025

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