Smart scan is the best option for discovering devices when ping is disabled in Fortinet networks.

What is the best discovery scan option for a network environment where ping is disabled on devices?

• A. Smart scan
• B. Range scan
• C. CMDB scan
• D. L2 scan

Answer: (A)

In a network environment where devices do not respond to ping, the smart scan option is the most effective choice. This is because a smart scan utilizes various methods to discover devices on the network beyond just ICMP echo requests (which is what ping uses). It can leverage protocols such as ARP, SNMP, or other network-based discovery mechanisms to identify devices. Unlike a range scan that systematically attempts to ping a range of IP addresses, or a CMDB scan that relies on an existing Configuration Management Database to identify devices, the smart scan is designed to adapt to conditions where traditional discovery methods fail. It can collect more comprehensive information about network devices based on available network protocols, making it suitable for environments where ping responses are not an option. The L2 scan focuses on Layer 2 frames and can reveal devices that are directly connected within the same broadcast domain. However, without ping responses, the smart scan's broader approach using various protocols gives it an advantage in discovering devices across more complex networks. Thus, the smart scan is the most appropriate choice for effectively identifying devices in an environment with disabled ping responses.

Outline

• Opening thought: In networks where devices ignore pings, discovery needs more than ICMP. Smart scan stands out.

• Quick landscape: four discovery styles and how they differ

• Smart scan: multi-protocol, adaptive, broader reach

• Range scan: ping-based, limited when ICMP is blocked

• CMDB scan: depends on a live CMDB, great when you already have one

• L2 scan: Layer 2 focus, local neighborhood only

• Why Smart scan wins in ping-disabled environments

• It leverages ARP, SNMP, and other methods to identify devices customers don’t hear back from

• It builds a richer picture of the network beyond simple reachability

• Practical tips to improve discovery in real networks

• Enable and configure SNMP, ARP visibility, and neighbor discovery

• Check ACLs, firewalls, and VLANs that can block discovery traffic

• Use CMDB as a supplemental source, not a replacement

• Common caveats and how to avoid them

• Devices behind/firewalled, IPv6 considerations, and mixed device types

• Bottom line: Smart scan as the go-to approach for ping-free networks

Article: When Ping Is Silent: Why Smart Scan Beats a Ping-Only Approach

Let me explain a simple reality many network teams face: some devices simply won’t answer a ping. They’re configured to ignore ICMP, or they sit behind a security policy that treats ping like a loud neighbor. In a Fortinet NSE 5 context, that means you need a discovery method that doesn’t hinge on every device saying “hello.” If you’re picking a discovery method for a network where ping is off the table, Smart scan is the most practical, reliable choice. It’s designed to work with what the network does use, not just what it doesn’t hear.

First, a quick tour of the four discovery styles you’ll encounter. Think of them as four different ways to reveal the neighborhood map, each with its own strengths and blind spots.

• Smart scan

This is the versatile, adaptive approach. Rather than rely on a single signal (like ICMP), Smart scan taps into a mix of discovery channels. It can use ARP to learn about devices on the same LAN, SNMP to pull device information and status, and other network-based cues to identify hosts. It’s the “get-the-job-done” method when the usual ping replies are missing. In short, Smart scan fills gaps that ping-based checks leave behind, giving you a broader, more accurate view of who’s actually on the network.

• Range scan

A Range scan is methodical and straightforward: sweep a range of IP addresses and see which ones respond. If ping is allowed, this works nicely. But when ICMP is blocked or rate-limited, Range scans stall or miss large swaths of devices. It’s reliable in a permissive environment, and brittle where ping is suppressed.

• CMDB scan

A CMDB scan leans on your configuration management database. If the database is current and comprehensive, this method can quickly surface devices that have already been cataloged. It’s less about discovering new, unrecorded assets and more about validating and enriching what you already know. When you have good data in the CMDB, CMDB scans are a powerful anchor.

• L2 scan

Layer 2 scans focus on the local broadcast domain—think devices you can see through direct Layer 2 frames. This can reveal neighboring devices that are physically close in the same switch or VLAN. But it’s limited to the local segment. Without higher-level signals like ping or SNMP, L2 scans can miss devices on other segments or behind routers.

Why Smart scan stands out when ping is off

Here’s the thing: Smart scan isn’t married to ICMP. It’s designed to be stubborn in a good way, adapting to conditions where traditional discovery approaches stumble. If a device never responds to a ping, Smart scan still has routes to learn about it.

• It uses ARP for direct neighbor awareness. ARP is often less restricted than ICMP because it’s a fundamental part of how devices map MAC addresses to IPs on the same network. This lets Smart scan discover devices that won’t respond to pings but do speak ARP.

• It leverages SNMP to pull both identity and status information. If SNMP is enabled and accessible, you can learn vendor, model, os version, and more—often with less noise than a ping-based sweep.

• It can exploit other discovery mechanisms that live in the network, from LLDP/CDP neighbors to even specific vendor protocols. The goal is to piece together a more complete picture of who’s there and how they’re connected, not just who answers a ping.

• It’s built to tolerate mixed environments. A real network isn’t uniform: VLANs, firewalls, virtualization overlays, and security policies all complicate visibility. Smart scan is designed to aggregate what is available across these layers, giving you a practical map you can trust for operational tasks.

Imagine you’re mapping a city when some streets refuse to light up at night. If you only use streetlights (ping), you’ll miss a lot. Smart scan brings in the other light sources—storefront cameras, traffic signals, even pedestrians with phones—to give you a fuller sense of the layout. That broader lens is what makes it especially valuable in a ping-disabled network.

Bringing it into practice: tips to boost discovery in real networks

If you’re aiming for a robust discovery process, here are pragmatic steps you can take to make Smart scan even more effective, without turning discovery into a scavenger hunt.

• Ensure SNMP visibility

• Verify SNMP is enabled on key devices, and that community strings or SNMP v3 credentials are correctly configured. SNMP is a workhorse for discovery and inventory data.

• Align SNMP access with your security policies. You want enough visibility to identify devices, but not so loose that it becomes a risk.

• Confirm ARP visibility

• Make sure devices aren’t dropping ARP traffic due to ACLs, firewall rules, or port security. ARP is often a dependable clue to what’s on the local network.

• Enable and rely on neighbor discovery

• LLDP (link-layer discovery) and, where applicable, CDP (Cisco) can reveal neighbors and layer-2 topology. These protocols help you infer devices that might not reply to pings but are still part of the fabric.

• Tidy up your data sources

• Treat a CMDB as a living resource. Use it to corroborate what Smart scan finds and to enrich it with asset ownership, location, and lifecycle data. It’s not a replacement for discovery, but a valuable companion.

• Check network boundaries

• Firewalls and segmentation can block discovery traffic. Review ACLs and zoning rules to ensure discovery traffic has a path, at least for the protocols your Smart scan relies on.

• Plan for IPv6

• If your environment uses IPv6, ensure your discovery strategy accounts for it. ARP is IPv4-only, so you’ll lean more on ND (Neighbor Discovery) and IPv6-enabled SNMP in those segments.

• Keep it practical

• Don’t expect one scan to do all the heavy lifting. Use Smart scan as the primary discovery method, with CMDB validation and, where appropriate, targeted L2 checks to fill in gaps.

Common pitfall checklist and how to dodge it

Even the best strategy can stumble if you overlook a few practical realities. Here are common snags and simple ways to sidestep them.

• The firewall party crasher

• Discovery traffic gets blocked. Solution: temporarily allow limited, controlled discovery traffic for the protocols you rely on (ARP, SNMP, LLDP). Then tighten rules again after you’ve mapped the network.

• Devices hiding behind VLANs

• Segmentation hides assets. Solution: leverage inter-VLAN routing views and ensure SNMP and LLDP reach across transit points where possible. Use a combination of data sources to infer devices on different segments.

• Mixed device behavior (legacy vs. modern)

• New devices eagerly respond to SNMP; old ones don’t. Solution: rely on multiple signals and cross-check with CMDB data. A hybrid approach reduces blind spots.

• IPv6 quirks

• Discovery confidence can dip in IPv6-only zones if you rely too much on IPv4-centric methods. Solution: incorporate IPv6-friendly discovery channels and make sure your SNMP and neighbor discovery work in IPv6 contexts.

• Overreliance on a single source

• One method isn’t enough. Solution: blend Smart scan with CMDB and, where useful, L2 reconnaissance to maintain a resilient view of the network.

A closing thought

If you’re building a reliable map of a network where devices won’t talk back to a ping, Smart scan is your most dependable ally. It’s designed to adapt, to pull signals from several protocols, and to deliver a coherent picture even when traditional discovery channels are silenced. That adaptability matters in real-world networks, where complexity isn’t a feature so much as a given.

Above all, think of discovery as a backstage pass to your network—the more signals you can gather, the better you can understand who’s actually active, how they’re connected, and where potential blind spots live. Smart scan gives you that richer, more actionable view without forcing you to rely on a single, fragile method.

If you’re exploring Fortinet NSE 5 capabilities, you’ll notice how these ideas surface in practical workflows: mapping devices, confirming inventory, validating topology, and supporting ongoing security operations. The goal isn’t to chase every gadget down a rabbit hole; it’s to build a confident, up-to-date picture of the network so you can respond quickly and intelligently when threats pop up or changes occur.

So, when ping is silent, your best bet is to lean into Smart scan. It’s the approach that respects reality—networks aren’t perfectly friendly to ICMP, and your discovery should reflect that. With the right configuration and a few complementary data sources, you’ll gain a clearer, more trustworthy view of your environment—and that clarity is what keeps security teams nimble and teams in control.