*Cold sites are the most cost-effective disaster recovery (DR) option since they require the least infrastructure investment. They provide space and power but no pre-configured systems.
*Hot sites (A) are fully operational and very expensive.
*Warm sites (D) offer some pre-configured hardware but still require setup, making them more costly than cold sites.
*Clusters (C) are active failover systems, not DR sites.
#Reference: CompTIA Network+ N10-009 Official Documentation - Disaster Recovery & Business Continuity Planning.

The issue is clearly related toDNS resolution, as IP-based connections succeed but domain name-based ones fail.
* D. dig(Domain Information Groper) is a DNS lookup tool used to troubleshoot DNS problems by querying name servers directly.
Other tools are less relevant here:
* A. tcpdumpis a packet analyzer and is more advanced for deeper traffic analysis.
* B. tracertis used to trace the route to a destination, not ideal for DNS issues.
* C. nmapis a port scanner and network mapper, not for resolving DNS problems.
#Reference:
CompTIA Network+ N10-009 Official Objectives: 5.1 - Given a scenario, use the appropriate network troubleshooting tools.

EIGRP(Enhanced Interior Gateway Routing Protocol) supports bothIPv4 and IPv6. While OSPFv3 is specific to IPv6 and RIPv2 only supports IPv4, EIGRP was extended to handle dual-stack environments efficiently.
Reference:Section 2.1 - Characteristics of Routing Technologies - "EIGRP"

See the solution configuration below in Explanation.
Explanation:
A screenshot of a computer AI-generated content may be incorrect.

A screenshot of a computer AI-generated content may be incorrect.
A screenshot of a computer AI-generated content may be incorrect.

* Understanding MTBF:
* Mean Time Between Failures (MTBF):A reliability metric that estimates the average time between successive failures of a device or system.
* Calculation and Importance:
* Calculation:MTBF is calculated as the total operational time divided by the number of failures during that period.
* Usage:Used by manufacturers and engineers to predict the lifespan and reliability of a device, helping in maintenance planning and lifecycle management.
* Comparison with Other Metrics:
* RTO (Recovery Time Objective):The maximum acceptable time to restore a system after a failure.
* RPO (Recovery Point Objective):The maximum acceptable amount of data loss measured in time.
* MTTR (Mean Time to Repair):The average time required to repair a device or system and return it to operational status.
* Application:
* MTBF is crucial for planning maintenance schedules, spare parts inventory, and improving the overall reliability of systems.
References:
* CompTIA Network+ study materials on reliability and maintenance metrics.