CompTIA Network+ (N10-009)Network TroubleshootingMedium
A network administrator is troubleshooting slow data transfers between two servers located in different data centers. Both servers are connected to 10 Gbps switch ports. Packet captures show that traffic from Server A to Server B is taking a path through a firewall, while traffic from Server B to Server A is taking a direct, unfirewalled path. What networking issue is MOST likely occurring?
- AVLAN mismatch.
- BDuplex mismatch.
- CAsymmetric routing.
- DSpanning Tree Protocol (STP) loop.
Show answer & explanationAnswer & explanation
Correct answer: C. Asymmetric routing.
Asymmetric routing occurs when packets in one direction traverse a different path than packets in the opposite direction. This can cause issues, especially with stateful firewalls that expect to see both halves of a conversation.
Why the other options are wrong
- A. A VLAN mismatch would typically prevent any communication between the servers, not just create different paths.
- B. A duplex mismatch would cause general performance issues on a single link, not different routing paths for traffic in opposing directions.
- D. An STP loop would cause broadcast storms and network meltdown, not simply different traffic paths for specific server communication.
Asymmetric Routing
Occurs when IP packets from a source to a destination take a different path than return packets from the destination to the source.
- Can cause issues with stateful firewalls, load balancers, and network monitoring tools.
- Often results in dropped packets or connection timeouts.
- Troubleshooted using traceroute from both ends and examining routing tables.
Memory trick: Routes Diverge, Stateful Firewalls Frown.