ISC2 CC Business Continuity, DR & Incident Response Practice Question
A mid-sized e-commerce company has a primary data center in New York and a disaster recovery site in Dallas. The application stack includes a web server, application server, and a PostgreSQL database. The database uses synchronous replication to the DR site. During a routine failover test, the IT team discovers that after failing over to Dallas, the web servers in New York continue to attempt connections to the original database IP, causing application errors. The DNS records have been updated to point to the DR database IP, but the web servers are not refreshing their DNS cache. The company uses a standard TTL of 300 seconds. The IT manager needs a solution that ensures minimal disruption during future failovers. Which action should be taken?
⚠ Common exam trap
ISC2 often tests the misconception that DNS TTL adjustments or cache clearing are sufficient for failover scenarios, but the trap here is that DNS-based solutions inherently introduce propagation delays and cache inconsistencies, whereas a virtual IP provides immediate, transparent failover without relying on DNS resolution.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implement a load balancer or proxy with a virtual IP that can be switched during failover, and update the web server configuration to connect to the virtual IP
It decouples the web servers from the database IP address by introducing a load balancer or proxy with a virtual IP (VIP). During failover, the VIP is simply moved to the DR database, and the web servers continue connecting to the same VIP without any DNS dependency or cache refresh issues. This eliminates the problem of stale DNS caches and ensures minimal disruption, as the connection endpoint remains constant.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add a static host entry in the web servers' hosts file pointing to the DR database IP
Why it's wrong here
Static entries require manual updates during failover, which is not scalable and prone to errors.
- ✗
Increase the DNS TTL to 86400 seconds to ensure all caches are updated quickly
Why it's wrong here
Increasing TTL would cause caches to hold stale records longer, making the problem worse.
- ✗
Configure the web servers to use a different DNS resolver that does not cache
Why it's wrong here
Changing DNS resolvers does not eliminate caching; most resolvers still cache.
- ✓
Implement a load balancer or proxy with a virtual IP that can be switched during failover, and update the web server configuration to connect to the virtual IP
Why this is correct
A virtual IP (VIP) can be moved between data centers via BGP or similar, so web servers always connect to the same IP, avoiding DNS caching issues.
Visual reference
Go deeper
Related to this question
Learn chapter
Business Continuity and Disaster Recovery
Key term
Business Continuity Planning
Business Continuity Planning is the process of creating a strategy to keep an organization's essential functions running during and after a major disruption.
Key term
DNS
DNS is the system that translates human-friendly domain names like example.com into machine-readable IP addresses so computers can find each other on a network.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CC practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CC exam.