CIW Internet Protocols & Network Foundations 2 — Questions and Answers
Question 1: Which DNS record type maps a hostname to an IPv4 address?
- MX
- CNAME
- A (Correct answer)
- PTR
Correct answer: A
An A (Address) record directly maps a domain name to a 32-bit IPv4 address.
Question 2: What is the default port used by SMTP for email submission?
- 25 (Correct answer)
- 110
- 143
- 993
Correct answer: 25
SMTP uses port 25 as its well-known port for server-to-server mail transfer and traditional mail submission.
Question 3: What is the key functional difference between POP3 and IMAP email protocols?
- POP3 keeps messages on the server; IMAP downloads and deletes them
- IMAP keeps messages on the server and syncs state; POP3 downloads and typically deletes them locally (Correct answer)
- They are functionally identical but use different ports
- POP3 is for incoming mail only; IMAP handles both incoming and outgoing mail
Correct answer: IMAP keeps messages on the server and syncs state; POP3 downloads and typically deletes them locally
IMAP synchronizes messages across multiple devices while leaving them on the server; POP3 downloads messages to one client and usually removes them from the server.
Question 4: Which DNS record type specifies the authoritative mail servers for a domain?
- A
- CNAME
- MX (Correct answer)
- NS
Correct answer: MX
An MX (Mail Exchanger) record identifies the mail servers responsible for accepting email on behalf of a domain.
Question 5: What is a DNS TTL (Time to Live) value used for?
- The maximum size of a DNS response packet
- The duration a DNS record can be cached by resolvers before being refreshed (Correct answer)
- The number of authoritative DNS servers that must store a record
- The encryption strength applied to DNS query responses
Correct answer: The duration a DNS record can be cached by resolvers before being refreshed
TTL tells caching resolvers how many seconds to store a DNS record before querying the authoritative server again for a fresh copy.
Question 6: FTP uses two separate ports — what are they and what does each do?
- Port 20 for data transfer, port 21 for control commands (Correct answer)
- Port 21 for data transfer, port 22 for control commands
- Port 80 for data transfer, port 21 for control commands
- Port 22 for both data transfer and control commands
Correct answer: Port 20 for data transfer, port 21 for control commands
FTP uses port 21 for the control connection (commands) and port 20 for the actual data transfer in active mode.
Question 7: Which DNS record type creates an alias from one hostname to another canonical hostname?
- A
- CNAME (Correct answer)
- MX
- TXT
Correct answer: CNAME
A CNAME (Canonical Name) record maps an alias domain name to the true (canonical) domain name, which is then resolved normally.
CIW Internet Protocols & Network Foundations 2
Which DNS record type maps a hostname to an IPv4 address?