Identify When Drops Are Occurring F5CAB5 Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   An administrator is troubleshooting a problem where a specific application is slow, but other applications are unaffected. The administrator checks the BIG-IP's interface statistics and sees that the 'Interface In Dropped' counter for the internal VLAN is increasing, but the 'Interface Out Dropped' counter is zero. What is the most likely cause of the drops?

   • AThe BIG-IP's CPU is overloaded, causing it to drop packets.
   • BThe BIG-IP is dropping packets because the connection table is full.
   • CThe internal network is congested, causing the BIG-IP to drop packets as they arrive from the server.
   • DThe client is sending too many requests, causing the BIG-IP to drop packets on the external interface.
   Reveal Solution Discussion Select an answer first
2. 2application · medium

   A BIG-IP administrator notices that the 'Interface In Dropped' counter for the external VLAN interface is increasing steadily, while the 'Interface Out Dropped' counter is zero. The BIG-IP is not experiencing any CPU or memory pressure, and the connection table is well below its limit. Users are reporting slow performance for traffic coming into the data center. Where are the drops most likely occurring?

   • AOn the client side because the client is sending malformed packets.
   • BOn the server-side interface due to outbound congestion from the server.
   • COn the BIG-IP's external interface due to inbound congestion or a buffer overflow.
   • DIn the BIG-IP's connection table because it is full.
   Reveal Solution Discussion Select an answer first
4. 3application · medium

   A BIG-IP administrator is troubleshooting a problem where clients are experiencing intermittent timeouts. The administrator runs tcpdump on the BIG-IP's client-facing interface and sees that the client's SYN packets are arriving, but the BIG-IP is not sending SYN-ACKs. The administrator also checks the BIG-IP's statistics and sees that the 'Client Packets Dropped' counter is increasing. What is the most likely cause of the timeouts?

   • AThe client is sending malformed SYN packets that are being rejected.
   • BThe BIG-IP is dropping the SYN packets before it can process them.
   • CThe network between the client and the BIG-IP is dropping the SYN-ACK packets.
   • DThe server is not responding to the BIG-IP's connection requests.
   Reveal Solution Discussion Select an answer first
5. 4foundation · medium

   Which tool or method is commonly used on a BIG-IP system to capture and inspect packet-level traffic to detect drops?

   • Atraceroute
   • Bping
   • Cnslookup
   • Dtcpdump
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6. 5application · medium

   An F5 BIG-IP administrator is troubleshooting intermittent application timeouts. Users report that some requests hang for several seconds before completing. A packet capture on the client side shows SYN packets sent but no SYN-ACK received for the affected connections. The administrator checks the BIG-IP's statistics and sees that the 'Client packets dropped' counter is incrementing. Which action should the administrator take next to determine whether the drops are occurring on the BIG-IP or further upstream?

   • AInspect the client's local firewall logs to confirm that the SYN packets are actually leaving the client machine.
   • BReview the BIG-IP's connection table to see if the connection is being created and then immediately deleted.
   • CCheck the server-side interface statistics for 'Server packets dropped' to see if the server is dropping the SYN.
   • DRun tcpdump on the BIG-IP's client-facing interface and look for SYN packets that are not followed by a SYN-ACK.
   Reveal Solution Discussion Select an answer first