N10-009 Exam Questions Tutorials

Definition of a Rogue DHCP Server:

A rogue DHCP server is an unauthorized DHCP server on a network, which can assign IP addresses to devices without proper control, leading to IP address conflicts.

Impact of a Rogue DHCP Server:

IP Address Conflicts: Multiple devices may receive the same IP address from different DHCP servers, causing network connectivity issues.

Network Disruption: Devices may be assigned incorrect network configuration settings, disrupting network services and connectivity.

Comparison with Other Attacks:

DNS poisoning: Alters DNS records to redirect traffic to malicious sites, but does not cause IP address conflicts.

Social engineering: Involves manipulating individuals to gain unauthorized access or information, not directly related to IP address conflicts.

Denial-of-service (DoS): Floods a network or service with excessive traffic to disrupt operations, but does not cause duplicate IP addresses.

Prevention and Detection:

Implement network access control measures to prevent unauthorized devices from acting as DHCP servers.

Use DHCP snooping on switches to allow DHCP responses only from authorized DHCP servers.

References:

CompTIA Network+ study materials on network security threats and mitigation techniques.

Role of the Hosts File:

The hosts file is a local file on a computer that maps hostnames to IP addresses. It can be used to override DNS resolution by providing a static mapping of a hostname to an IP address.

Common Issues with the Hosts File:

If an incorrect IP address is mapped to a hostname in the hosts file, it can cause the computer to resolve the hostname to the wrong IP address. This can lead to navigation issues for specific websites while other users, relying on DNS, do not face the same problem.

Why Other Options are Less Likely:

Self-signed certificate: Relates to SSL/TLS and would cause a security warning, not a navigation failure.

Nameserver record: Affects all users, not just one.

IP helper: Used to forward DHCP requests and is unrelated to DNS resolution issues.

Troubleshooting Steps:

Check the hosts file on the affected user's computer (C:\Windows\System32\drivers\etc\hosts on Windows or /etc/hosts on Unix/Linux).

Look for entries that map the problematic hostname to an incorrect IP address and correct or remove them.

References:

CompTIA Network+ study materials and system administration documentation.