DHCP and DNS Flashcards
(50 cards)
What is the primary purpose of DHCP?
a) To resolve domain names to IP addresses
b) To automatically assign IP addresses to network devices
c) To encrypt network traffic
d) To route packets between networks
Answer: b
Which port does DHCP use for client-server communication?
a) TCP 53
b) UDP 67 and 68
c) TCP 80
d) UDP 161
Answer: b
What is the first message sent by a DHCP client to obtain an IP address?
a) DHCP Offer
b) DHCP Request
c) DHCP Discover
d) DHCP Acknowledge
Answer: c
Which DHCP message is sent by the server to confirm an IP address assignment?
a) DHCP Offer
b) DHCP Request
c) DHCP Discover
d) DHCP Acknowledge (ACK)
Answer: d
What is a DHCP lease time?
a) The time taken to discover a DHCP server
b) The duration for which an IP address is assigned to a client
c) The time taken to renew an IP address
d) The interval between DHCP Offers
Answer: b
Which DHCP message does a client send to renew its IP address before lease expiration?
a) DHCP Request (unicast)
b) DHCP Discover (broadcast)
c) DHCP Release
d) DHCP Decline
Answer: a
What is the purpose of a DHCP relay agent?
a) To assign static IP addresses
b) To forward DHCP messages between different subnets
c) To encrypt DHCP traffic
d) To resolve hostnames
Answer: b
Which command is used to configure a Cisco router as a DHCP server?
a) ip dhcp pool
b) ip helper-address
c) dhcp enable
d) ip dhcp-client
Answer: a
What is the default lease time for DHCP-assigned addresses if not specified?
a) 1 hour
b) 24 hours
c) 7 days
d) 30 minutes
Answer: b
Which DHCP message does a client send to release its IP address voluntarily?
a) DHCP Request
b) DHCP Release
c) DHCP Decline
d) DHCP Inform
Answer: b
What is the purpose of the ip helper-address command?
a) To configure a router as a DHCP server
b) To forward DHCP broadcasts to a specific server
c) To assign a static IP address
d) To disable DHCP services
Answer: b
Which DHCP option is used to provide the default gateway address?
a) Option 3
b) Option 6
c) Option 15
d) Option 66
Answer: a
What happens if a DHCP server is unavailable?
a) The client uses a static IP
b) The client uses APIPA (169.254.x.x)
c) The client keeps the old IP forever
d) The client stops functioning
Answer: b
Which command shows DHCP lease information on a Cisco router?
a) show dhcp lease
b) show ip dhcp binding
c) show running-config
d) show dhcp server
Answer: b
What is DHCP snooping used for?
a) To prevent rogue DHCP servers
b) To speed up DHCP requests
c) To encrypt DHCP traffic
d) To assign static IPs
Answer: a
What is the primary function of DNS?
a) To assign IP addresses dynamically
b) To resolve domain names to IP addresses
c) To encrypt web traffic
d) To route packets between networks
Answer: b
Which port does DNS primarily use?
a) TCP 80
b) UDP 53
c) TCP 443
d) UDP 67
Answer: b
What is a DNS resolver?
a) A server that stores DNS records
b) A client that queries DNS servers
c) A protocol for secure DNS
d) A type of DNS attack
Answer: b
Which DNS record maps a hostname to an IPv4 address?
a) AAAA
b) MX
c) A
d) CNAME
Answer: c
What does an MX record specify?
a) The mail server for a domain
b) The IPv6 address of a host
c) An alias for a domain
d) The start of authority for a domain
Answer: a
Which DNS record is used for IPv6 addresses?
a) A
b) AAAA
c) PTR
d) CNAME
Answer: b
What is a CNAME record used for?
a) To define an alias for a hostname
b) To specify an IPv4 address
c) To point to a mail server
d) To provide DNSSEC authentication
Answer: a
What is the purpose of a PTR record?
a) To map an IP address to a hostname (reverse DNS)
b) To define a mail server
c) To alias a domain name
d) To provide DNSSEC
Answer: a
Which command is used to test DNS resolution in Windows?
a) ping
b) tracert
c) nslookup
d) ipconfig
Answer: c
