What is the primary purpose of a firewall in a TCP/IP network?

To translate domain names to IP addresses

To assign IP addresses to devices

To filter network traffic based on security rules

A technician is configuring a new HMI to connect to a historian server by hostname 'historian.corp.local'. The HMI can ping the server's IP address but cannot resolve the hostname. The technician checks the DNS server settings on the HMI and they are correct. What is the most likely issue?

The HMI's hosts file has an incorrect entry for the historian.

The HMI is using a different DNS suffix than the historian's domain.

The DNS server does not have a forward lookup zone for 'corp.local'.

The historian's IP address is not reachable from the HMI.

A control system engineer is troubleshooting a DNS resolution issue in a hybrid OT/IT environment. The OT network uses a local DNS server that forwards queries to an IT DNS server. A new HMI cannot resolve 'plc5.plant.local', but other HMIs can. The engineer verifies that the HMI's DNS settings are correct and that it can ping the DNS server. What is the most likely cause?

The local DNS server does not have a zone for 'plant.local'.

The HMI's hosts file has an incorrect entry for 'plc5.plant.local'.

The HMI's DNS cache has a negative entry for 'plc5.plant.local'.

A SCADA network uses a firewall to separate the OT network from the corporate IT network. The firewall is configured with an allow rule for TCP port 502 from the IT subnet to the OT subnet. What is the primary purpose of this rule?

To provide encrypted remote access to the OT network.

To permit Modbus TCP traffic from the IT network to reach OT devices.

To enable DNS name resolution for OT devices.

To block all UDP traffic between the two networks.

EC-CouncilICS/SCADA Cybersecurity

Domain 2Objective 5

Components of TCP/IP Networks ICSSCADA Practice Questions (Page 3)

Part of the TCP/IP and ICS/SCADA Protocols domain, which makes up ~13% of our current practice bank. EC-Council does not publish an official question count, but from its 120-minute exam (~50–80 total, ~7–10 in this domain), expect 1–2 from this objective — we provide 45 practice questions to prepare you well beyond it. (estimate)

45questions here

9free pages

8concepts

Questions 11–15

11foundation · easy
What is the primary purpose of a firewall in a TCP/IP network?
Select an answer first
12application · medium
A technician is configuring a new HMI to connect to a historian server by hostname 'historian.corp.local'. The HMI can ping the server's IP address but cannot resolve the hostname. The technician checks the DNS server settings on the HMI and they are correct. What is the most likely issue?
Select an answer first
13expert · hard
A control system engineer is troubleshooting a DNS resolution issue in a hybrid OT/IT environment. The OT network uses a local DNS server that forwards queries to an IT DNS server. A new HMI cannot resolve 'plc5.plant.local', but other HMIs can. The engineer verifies that the HMI's DNS settings are correct and that it can ping the DNS server. What is the most likely cause?
Select an answer first
14foundation · easy
Which protocol operates at the Internet layer of the TCP/IP model?
Select an answer first
15application · medium
A SCADA network uses a firewall to separate the OT network from the corporate IT network. The firewall is configured with an allow rule for TCP port 502 from the IT subnet to the OT subnet. What is the primary purpose of this rule?
Select an answer first

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Components of TCP/IP Networks ICSSCADA Practice Questions (Page 3)

Questions 11–15

What is the primary purpose of a firewall in a TCP/IP network?

A technician is configuring a new HMI to connect to a historian server by hostname 'historian.corp.local'. The HMI can ping the server's IP address but cannot resolve the hostname. The technician checks the DNS server settings on the HMI and they are correct. What is the most likely issue?

Which protocol operates at the Internet layer of the TCP/IP model?

A SCADA network uses a firewall to separate the OT network from the corporate IT network. The firewall is configured with an allow rule for TCP port 502 from the IT subnet to the OT subnet. What is the primary purpose of this rule?

Keep studying — TCP/IP and ICS/SCADA Protocols