What command can be used to verify IP connectivity to an application tier from a NoSQL database server?

Using the 'ping' command is the most effective way to verify IP connectivity. This command sends Internet Control Message Protocol (ICMP) Echo Request messages to the target server, such as the application tier from the NoSQL database server, and waits for Echo Reply messages. If the application tier is reachable, the ping command will provide response times, indicating successful connectivity and communication between the two points.

Other commands listed serve different purposes. For example, 'arproute' is not a standard command found on all systems and is typically associated with routing ARP requests, which is not directly applicable to checking IP connectivity. The 'netstat' command displays network connections, routing tables, and network statistics but does not actively test connectivity. On the other hand, 'tcpdump' is a packet analyzer used to capture and analyze network traffic, which is useful for diagnosing issues but does not provide a simple confirmation of connectivity like ping does. Therefore, 'ping' is the best choice for this specific scenario.