CS6250 Computer Networks – Exam 1
Practice Exam Questions And Correct
Answers Plus Rationales 2026 Q&A | Instant
Download Pdf.
Introduction
Welcome to the practice exam for CS6250 (Georgia Tech OMSCS) – Computer Networks.
This exam covers foundational topics typically assessed in Exam 1, including:
Application Layer: HTTP, DNS, email protocols, Web architecture
Transport Layer: UDP, TCP (segmentation, reliability, flow control, congestion control)
Network Layer: IP addressing, routing algorithms (distance vector, link state),
forwarding, NAT, DHCP
Data Link Layer: Framing, error detection, MAC protocols, Ethernet, switching
Network Security basics: Firewalls, DoS, encryption at different layers
1. Which transport protocol does HTTP typically use?
A) UDP
B) TCP
C) ICMP
D) SCTP
HTTP uses TCP because it requires reliable, ordered delivery of web
objects.
2. What is the default port number for HTTPS?
A) 80
B) 443
C) 8080
D) 22
*HTTPS (HTTP over SSL/TLS) uses port 443; HTTP uses port 80.*
,3. Which DNS record type maps a domain name to an IPv4 address?
A) AAAA
B) A
C) CNAME
D) MX
A record is for IPv4; AAAA is for IPv6; CNAME is alias; MX is mail
exchange.
4. In HTTP/1.1, what mechanism allows multiple requests to be sent without waiting for
responses?
A) Persistent connections
B) Pipelining
C) Multiplexing
D) Head-of-line blocking
Pipelining sends multiple requests consecutively on the same persistent
connection, though responses must arrive in order.
5. Which DNS record is used to delegate a subdomain to a different name server?
A) SOA
B) PTR
C) NS
D) TXT
NS records specify the authoritative name servers for a domain or
subdomain.
6. What type of DNS query asks the local server to return the answer from its cache or
recursively resolve it?
A) Iterative query
B) Non-recursive query
C) Recursive query
D) Inverse query
A recursive query forces the DNS server to fully resolve the name and
return the answer.
7. Which of the following is not a characteristic of SMTP?
A) Uses push semantics
B) Uses port 25 by default
C) Uses a separate connection for each recipient
D) Stores mail on the server until retrieved
, SMTP can send to multiple recipients in one connection; it is a push
protocol. Storing mail is a function of the mail server, not SMTP itself.
8. The command dig +trace performs:
A) A recursive DNS lookup
B) An iterative DNS lookup starting from the root
C) A reverse DNS lookup
D) A DNS zone transfer
+trace makes dig follow the delegation chain from the root servers
iteratively.
9. Which HTTP method is idempotent and typically used to retrieve a resource?
A) POST
B) GET
C) PUT
D) DELETE
GET is safe (no server state change) and idempotent; POST is not
idempotent.
10. What is the primary purpose of the HTTP Host header?
A) To specify the client’s IP address
B) To enable virtual hosting
C) To indicate the user-agent
D) Both B and the ability to host multiple domains on one IP
The Host header allows a single web server to serve multiple domain
names on the same IP address.
11. Which DNS record type is used for reverse lookup (IP to name)?
A) NS
B) CNAME
C) PTR
D) SOA
PTR (pointer) records map an IP address to a canonical domain name.
12. What does the HTTP If-Modified-Since header enable?
A) Content negotiation
B) Conditional GET
C) Range requests
D) Persistent connections
Practice Exam Questions And Correct
Answers Plus Rationales 2026 Q&A | Instant
Download Pdf.
Introduction
Welcome to the practice exam for CS6250 (Georgia Tech OMSCS) – Computer Networks.
This exam covers foundational topics typically assessed in Exam 1, including:
Application Layer: HTTP, DNS, email protocols, Web architecture
Transport Layer: UDP, TCP (segmentation, reliability, flow control, congestion control)
Network Layer: IP addressing, routing algorithms (distance vector, link state),
forwarding, NAT, DHCP
Data Link Layer: Framing, error detection, MAC protocols, Ethernet, switching
Network Security basics: Firewalls, DoS, encryption at different layers
1. Which transport protocol does HTTP typically use?
A) UDP
B) TCP
C) ICMP
D) SCTP
HTTP uses TCP because it requires reliable, ordered delivery of web
objects.
2. What is the default port number for HTTPS?
A) 80
B) 443
C) 8080
D) 22
*HTTPS (HTTP over SSL/TLS) uses port 443; HTTP uses port 80.*
,3. Which DNS record type maps a domain name to an IPv4 address?
A) AAAA
B) A
C) CNAME
D) MX
A record is for IPv4; AAAA is for IPv6; CNAME is alias; MX is mail
exchange.
4. In HTTP/1.1, what mechanism allows multiple requests to be sent without waiting for
responses?
A) Persistent connections
B) Pipelining
C) Multiplexing
D) Head-of-line blocking
Pipelining sends multiple requests consecutively on the same persistent
connection, though responses must arrive in order.
5. Which DNS record is used to delegate a subdomain to a different name server?
A) SOA
B) PTR
C) NS
D) TXT
NS records specify the authoritative name servers for a domain or
subdomain.
6. What type of DNS query asks the local server to return the answer from its cache or
recursively resolve it?
A) Iterative query
B) Non-recursive query
C) Recursive query
D) Inverse query
A recursive query forces the DNS server to fully resolve the name and
return the answer.
7. Which of the following is not a characteristic of SMTP?
A) Uses push semantics
B) Uses port 25 by default
C) Uses a separate connection for each recipient
D) Stores mail on the server until retrieved
, SMTP can send to multiple recipients in one connection; it is a push
protocol. Storing mail is a function of the mail server, not SMTP itself.
8. The command dig +trace performs:
A) A recursive DNS lookup
B) An iterative DNS lookup starting from the root
C) A reverse DNS lookup
D) A DNS zone transfer
+trace makes dig follow the delegation chain from the root servers
iteratively.
9. Which HTTP method is idempotent and typically used to retrieve a resource?
A) POST
B) GET
C) PUT
D) DELETE
GET is safe (no server state change) and idempotent; POST is not
idempotent.
10. What is the primary purpose of the HTTP Host header?
A) To specify the client’s IP address
B) To enable virtual hosting
C) To indicate the user-agent
D) Both B and the ability to host multiple domains on one IP
The Host header allows a single web server to serve multiple domain
names on the same IP address.
11. Which DNS record type is used for reverse lookup (IP to name)?
A) NS
B) CNAME
C) PTR
D) SOA
PTR (pointer) records map an IP address to a canonical domain name.
12. What does the HTTP If-Modified-Since header enable?
A) Content negotiation
B) Conditional GET
C) Range requests
D) Persistent connections
