Which directive in the llttab file defines a network interface for a heartbeat? 07/30/2017 – by Mod_GuideK 0 Which directive in the llttab file defines a network interface for a heartbeat? A. Nic B. Link C. Heartbeat D. Hbdev SHOW ANSWERSCorrect Answer: B Explanation/Reference: Explanation: Download Printable PDF. VALID exam to help you PASS.