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What is DHCP?
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DHCP is a protocol that automatically assigns IP addresses and network settings to devices (hosts) that connect to the network.
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What is a DHCP scope?
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A DHCP scope is the range of IP addresses a DHCP server can assign to hosts on a subnet, excluding manually configured static addresses.
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What is a DHCP lease?
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A DHCP lease is the period of time a host can use an IP address assigned by a DHCP server before it must renew the lease.
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What is the purpose of a DHCP reservation?
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A DHCP reservation ensures specific devices always get the same IP address from the DHCP server based on their MAC address.
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What ports are used by DHCP?
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DHCP uses UDP port 67 for the server and UDP port 68 for the client.
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What is DNS?
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DNS is a system that translates human-readable domain names (like www.example.com) into IP addresses.
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What is a Fully Qualified Domain Name (FQDN)?
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An FQDN is the complete domain name for a host, consisting of a host name and domain name, such as pc.example.com.
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What are the three main types of Top-Level Domains (TLDs)?
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Generic TLDs (e.g., .com, .org), Sponsored TLDs (e.g., .gov, .edu), and Country Code TLDs (e.g., .uk, .ca).
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What port does DNS use?
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DNS uses TCP/UDP port 53.
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What is the hierarchy of DNS?
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Root (.), Top-Level Domain (e.g., .com), Domain (e.g., example), and Host (e.g., www).
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What is the first step in the DNS resolution process?
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The stub resolver checks its local cache for the IP address of the requested domain name.
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What happens if the DNS resolver doesn't find an address locally?
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The query is forwarded to a local DNS server, which may recursively query root, TLD, and authoritative servers to resolve the name.
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What does a DNS server do after resolving a query?
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It returns the IP address to the client, which caches the result for future queries.
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What is an A record?
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An A record maps a host name to an IPv4 address.
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What is an AAAA record?
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An AAAA record maps a host name to an IPv6 address.
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What is an MX record?
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An MX record identifies email servers for a domain.
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What is a TXT record used for?
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A TXT record stores free-form text in the DNS, commonly used to verify email services and block spam.
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What is SPF (Sender Policy Framework)?
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SPF is a DNS TXT record that specifies which hosts are authorized to send email for a domain.
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What is DKIM (DomainKeys Identified Mail)?
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DKIM uses cryptography to validate the source server for an email message via a public key stored in a DNS TXT record.
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What is DMARC?
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DMARC ensures that SPF and DKIM are being used effectively, allowing domain owners to specify how email authentication failures are handled.
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What is a VLAN?
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A VLAN is a virtual group of network devices configured to act as if they are on the same physical network, even if they are not.
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How are VLANs assigned?
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VLANs are assigned using VLAN IDs (from 2 to 4094), which divide a switch into separate broadcast domains.
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What is the default VLAN?
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The default VLAN is VLAN 1, and all ports on a managed switch are part of this VLAN unless configured otherwise.
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What is required for communication between VLANs?
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Communication between VLANs requires an IP router, and each VLAN must have its own subnet and IP address range.
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What are the benefits of VLANs?
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VLANs improve network performance, enhance security, and allow traffic management by segmenting broadcast domains and prioritizing certain types of traffic, like VoIP.
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What is a VPN?
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A VPN is a technology that allows remote users to securely connect to a local network over the Internet.
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How does a VPN ensure security?
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A VPN uses encryption and secure protocols to create a protected tunnel through the Internet.
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What is the main use case for a VPN?
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A VPN is used for remote access to a company's network by teleworkers or for site-to-site connections between branch offices.
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How does a VPN handle network access?
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Once the VPN is established, the remote computer functions as if it is part of the local network, although performance depends on Internet bandwidth.