CompTIA Network+ 练习

A network connects devices so they can share data and resources. It is not a single computer, storage device, or browser.

An IP address identifies a device on a network at the network layer. MAC addresses are hardware addresses, and passwords or cables are different.

A MAC address is the physical address assigned to a network interface. IP addresses are logical, and DNS or firewall rules are different.

A subnet mask separates the network and host portions of an address. Encryption, DNS resolution, and MAC assignment are separate functions.

DNS translates names like example.com into IP addresses. DHCP assigns addresses, firewalls filter, and encryption protects data.

DHCP assigns IP configuration to clients automatically. DNS resolves names, routers forward packets, and encryption protects data.

TCP provides reliable, ordered delivery with connections. UDP is connectionless, routing protocols forward packets, and wireless standards define radio links.

UDP sends datagrams without establishing a connection, which reduces overhead. TCP is reliable, and DNS servers or switches are devices.

Routers forward packets between networks using IP addresses. Switches connect LAN devices, and cables or printers are not routers.

Switches forward frames between devices on a LAN. Routers connect networks, modems convert signals, and firewalls filter traffic.

Firewalls permit or block traffic according to rules. Access points provide Wi-Fi, switches connect LAN devices, and DNS servers resolve names.

Bandwidth measures how much data a link can carry. Latency measures delay, device count is scale, and encryption strength is security.

Ethernet is a wired LAN technology that transmits frames. Wi-Fi is wireless, OSPF is routing, and DNS resolves names.

Wi-Fi is a wireless LAN technology using radio waves. Ethernet is wired, and routing or VPN are different.

A VLAN creates separate broadcast domains on a switch. It is not a cable, firewall rule, or DNS zone.

A VPN encrypts traffic through a tunnel. VLANs segment traffic, access points provide Wi-Fi, and cables are physical.

Load balancers spread requests across servers for availability. Firewalls block, DNS resolves, and switches connect.

A proxy acts on behalf of clients for web or other traffic. It is not a router, tester, or printer.

Hubs broadcast to all connected ports, while switches filter by MAC. Routers connect networks and firewalls filter traffic.

An access point bridges wireless clients to the wired network. Routers forward between networks, and switches or firewalls are different.

PoE supplies power through Ethernet cabling to devices such as access points. It is not wireless power, firewall, or routing.

Fiber optic cables send light pulses, offering high speed and low interference. Copper uses electricity, and antennas are wireless.

Patch panels organize and terminate cabling. They do not filter, resolve names, or balance load.

A gateway translates between different protocols or networks. It is not a port, cable, or DNS record.

SNMP lets administrators collect metrics from network devices. DNS resolves names, DHCP assigns addresses, and encryption protects data.

Syslog centralizes log messages from devices. Bandwidth monitors measure traffic, ping tests connectivity, and DHCP assigns addresses.

An SLA defines agreed service expectations such as uptime and response time. It is not cabling, firewalls, or routing.

Uptime measures availability. Downtime is offline time, boot time is startup, and response time is latency.

Baselines record normal performance so anomalies can be detected. Policies, backups, and cable tests are different.

Change management plans, reviews, and documents changes to reduce risk. It is not backup, firewall, or monitoring alone.

Incidents are unplanned disruptions. Maintenance, backups, and account creation are planned operations.

Runbooks contain repeatable operational steps. Logs, DNS zones, and ports are not procedures.

Backups protect data so it can be restored. Firewalls, routing tables, and cables are not backups.

Disaster recovery plans restore services after major outages. Monitoring, patching, and VLANs are separate.

Patches fix bugs and security vulnerabilities. Cables, firewall rules, and ports are not patches.

SNMP, Syslog, and Ping help monitor and test networks. A spreadsheet is not a network monitoring tool.

Authentication confirms identity. Authorization grants access, encryption protects data, and firewalls filter traffic.

Authorization decides what an authenticated user can do. Authentication verifies identity, and encryption or blocking are different.

Encryption protects confidentiality. Firewalls filter, DNS resolves, and DHCP assigns addresses.

A DMZ hosts public-facing services while limiting access to internal networks. It is not a private VLAN, log, or DNS zone.

WPA3 is the latest Wi-Fi security standard. OSPF is routing, DNS resolves names, and cabling is physical.

802.1X authenticates devices before allowing network access on a port. It is not a frequency, routing protocol, or cable.

Zero trust verifies identity and context for each request. It does not trust internal users automatically or remove passwords.

DoS attacks overwhelm services to deny access. Password attacks, phishing, and DNS caches are different.

Malware includes viruses, ransomware, and trojans. Firewalls, backups, and cables are defenses or infrastructure.

A VPN concentrator handles many VPN connections. Access points, DNS servers, and load balancers have different roles.

ACLs filter traffic by rules. DNS records resolve names, routing tables forward packets, and MAC tables switch frames.

MFA combines factors such as something you know, have, or are, which makes accounts more secure.

Ping sends ICMP echo requests to test reachability. DNS resolves names, route commands show tables, and encryption protects data.

Traceroute lists hops along a path. DNS tests resolve names, DHCP assigns addresses, and firewalls filter.

nslookup queries DNS. Cable testers check wiring, ipconfig shows IP config, and packet capture inspects traffic.

ipconfig displays Windows IP settings. nslookup tests DNS, traceroute shows paths, and packet capture inspects traffic.

netstat shows active connections and listening ports. DNS, cabling, and VLAN configuration are different.

Packet capture records traffic for inspection. Firewalls filter, backups store data, and DNS queries resolve names.

127.0.0.1 is the IPv4 loopback address used to test the local host. The other addresses are not loopback.

Connectivity issues often come from cables, Wi-Fi, or IP configuration. Replacing hardware or reinstalling is not the first step.

Crossover cables connect similar devices directly. Straight-through cables connect computers to switches, and PoE delivers power.

Speed tests measure throughput and latency. DNS tests, ipconfig, and packet capture have other purposes.

Troubleshooting begins by identifying symptoms and scope. Replacing or rebooting without diagnosis is inefficient.

Ping tests connectivity, traceroute shows the path, nslookup queries DNS, and netstat shows connections.