CompTIA Updated N10-009 Exam Questions and Answers by moshe

Understanding Subnetting:

The subnet mask 255.255.255.240 (or /28) indicates that each subnet has 16 IP addresses (14 usable addresses, 1 network address, and 1 broadcast address).

Calculating the Subnet Range:

Subnet Calculation: For the IP address 10.0.0.95 with a /28 subnet mask:

Network address: 10.0.0.80

Usable IP range: 10.0.0.81 to 10.0.0.94

Broadcast address: 10.0.0.95

Router Interface Configuration:

Broadcast Address Issue: The IP address 10.0.0.95 is the broadcast address for the subnet 10.0.0.80/28. Configuring a router interface with the broadcast address will cause routing issues as it is not a valid host address.

Comparison with Other Options:

The web server is in a different subnet: The web server (10.0.0.81) is within the same subnet range (10.0.0.80/28).

The IP address space is a class A network: While 10.0.0.0 is a Class A network, this does not explain the routing issue caused by the broadcast address.

The subnet is in a private address space: The private address space designation (RFC 1918) does not impact the routing issue related to the broadcast address configuration.

Resolution:

Reconfigure the router interface with a valid host IP address within the usable range, such as 10.0.0.94.

The tracert (Traceroute) command is used to determine the path packets take from the source to the destination. It helps in identifying routing issues by showing each hop the packets pass through, along with the time taken for each hop. This command can pinpoint where the connection is failing or experiencing delays, making it an essential tool for troubleshooting routing issues.References: CompTIA Network+ study materials and common network troubleshooting commands. ​

Port 587 is used for secure email submission. This port is designated for message submission by mail clients to mail servers using the SMTP protocol, typically with STARTTLS for encryption.

Port 25: Traditionally used for SMTP relay, but not secure and often blocked by ISPs for outgoing mail due to spam concerns.

Port 110: Used for POP3 (Post Office Protocol version 3), not typically secured.

Port 143: Used for IMAP (Internet Message Access Protocol), which can be secured with STARTTLS or SSL/TLS.

Port 587: Specifically used for authenticated email submission (SMTP) with encryption, ensuring secure transmission of email from clients to servers.

Network References:

CompTIA Network+ N10-007 Official Certification Guide: Discusses email protocols and ports, including secure email transmission.

Cisco Networking Academy: Provides training on securing email communications and the use of appropriate ports.

Network+ Certification All-in-One Exam Guide: Explains email protocols, ports, and security considerations for email transmission.

IPSec (Internet Protocol Security) is the best choice for secure communication over the internet, as it provides encryption, authentication, and data integrity. It is widely used in VPNs and site-to-site secure tunnels.

Breakdown of Options:

A. DCI (Data Center Interconnect) – A general term for linking data centers, but it doesn’t specify a secure tunneling protocol.

B. GRE (Generic Routing Encapsulation) – Encapsulates traffic but lacks encryption, making it less secure than IPSec.

C. VXLAN (Virtual Extensible LAN) – Used for Layer 2 network overlays, not for securing communication over the internet.

D. IPSec – ✅ Correct answer. Provides encryption, authentication, and integrity for data over the internet.