Cisco Certified Network Associate (CCNA) Practice Exam

How can you ensure connectivity between two PPP devices when troubleshooting?

1. Ensure compatibility of transport protocols

2. Verify IP routing tables

3. Check physical connections

4. Test firewall rules

The correct answer is: Check physical connections

Ensuring connectivity between two PPP (Point-to-Point Protocol) devices involves checking physical connections as a foundational step. PPP relies on a physical layer connection, so if the physical layer is compromised or incorrectly configured, no data can be transmitted between the devices. This includes examining cables, connectors, and interface statuses to confirm they are functioning correctly and are properly connected. If the physical connections are sound, you can then move on to other factors like ensuring compatibility of transport protocols, verifying IP routing tables, and testing firewall rules. However, if there is no physical link, none of those other considerations would matter since the devices cannot communicate at all. Therefore, verifying the physical layer is the critical first step in troubleshooting connectivity issues between PPP devices.