ICMP (Internet Control Message Protocol) is used for diagnostics and error reporting in IP networks. It is encapsulated directly within IP datagrams and not over UDP or TCP. It does not guarantee delivery — it merely provides feedback about problems (e.g., host unreachable, time exceeded).
MTCNA Course Material – ICMP and Network Tools:
“ICMP is used for error messages and operational queries such as ping and destination unreachable. It is encapsulated in IP and does not use TCP or UDP.”
René Meneses MTCNA Study Guide – ICMP Section:
“ICMP provides diagnostic information. It is a Layer 3 protocol encapsulated directly in IP. It does not provide guaranteed delivery.”
MikroTik Wiki – ICMP Overview:
“ICMP packets are carried in IP packets and used for control messages. They are not transported using TCP or UDP.”
Breakdown:
Statement 1: False – ICMP does not guarantee delivery
Statement 2: True – provides network problem feedback
Statement 3: True – encapsulated in IP
Statement 4: False – ICMP is not encapsulated in UDP
Correct set: 2 and 3
Final Answer: BQUESTION NO: 106 [RouterOS Introduction]
Which Layer 4 protocol is used for a Telnet connection?
A. IP
B. TCP
C. TCP/IP
D. UDP
Answer: B
Telnet is a protocol used to access remote devices via command-line over the network. It operates over TCP at Layer 4, using port 23.
MTCNA Course Material – Layer 4 Protocols:
“Telnet uses TCP port 23 for remote shell access. TCP ensures ordered and reliable delivery of commands and responses.”
René Meneses MTCNA Study Guide – TCP/IP Protocols:
“Telnet is an Application Layer protocol using TCP as its transport protocol.”
MikroTik Wiki – Telnet Access:
“Telnet communicates over TCP. It does not use UDP.”
Other options:
A. IP is a Layer 3 protocol
C. TCP/IP is a model, not a single protocol
D. Telnet does not use UDP
Final Answer: BQUESTION NO: 107 [RouterOS Introduction]
Which of the following are layers in the TCP/IP model?
Application
Session
Transport
Internet
Data Link
Physical
A. 1 and 2
B. 1, 3 and 4
C. 2, 3 and 5
D. 3, 4 and 5
Answer: B
The TCP/IP model has four layers:
Session is part of the OSI model, not TCP/IP.
MTCNA Course Material – TCP/IP vs OSI Model:
“The TCP/IP model has Application, Transport, Internet, and Network Access layers. Application includes OSI’s Session, Presentation, and Application layers.”
René Meneses MTCNA Guide – Model Comparison:
“The TCP/IP model consists of: Application, Transport, Internet, and Network Access (which covers Data Link and Physical). Session layer is part of OSI.”
So, correct TCP/IP layers from the given list:
Application (✔)
Transport (✔)
Internet (✔)
Session is not part of TCP/IP model.
Final Answer: BQUESTION NO: 108 [RouterOS Introduction]
Which statements are true regarding ICMP packets?
They acknowledge receipt of a TCP segment.
They guarantee datagram delivery.
They can provide hosts with information about network problems.
They are encapsulated within IP datagrams.
A. 1 only
B. 2 and 3
C. 3 and 4
D. 2, 3 and 4
Answer: C
Reiterating from earlier:
ICMP does not acknowledge TCP segments; that’s TCP’s job.
ICMP does not guarantee delivery; it’s an unreliable protocol.
ICMP does provide diagnostics (e.g., unreachable, TTL exceeded).
ICMP is encapsulated directly in IP, not over TCP/UDP.
MTCNA Course Material – ICMP Behavior:
“ICMP is used for control messages like ping and unreachable. It provides feedback and is encapsulated in IP.”
René Meneses MTCNA Study Guide – ICMP & IP Layer:
“ICMP is a Layer 3 protocol, not used to acknowledge TCP, and is wrapped in IP datagrams.”
Correct:
Statement 3: True
Statement 4: True
