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LinkRunner® AT 4000

Smart Network & Cable Tester

LinkRunner® AT 4000

Smart Network & Cable Tester

The LinkRunner AT 4000 is a cutting-edge network cable tester for modern networking tasks and infrastructural diagnostics. Designed for network engineers requiring a robust toolset for both fiber and Multigigabit Ethernet environments, it offers:

  • Advanced network discovery and topology mapping.
  • Comprehensive diagnostics and troubleshooting features, enhancing network visibility and operational efficiency.
  • A robust set of automated tests for precise network validation and troubleshooting, ensuring seamless moves, adds, and changes.

Key Features

How to use the LinkRunner AT 4000

Test it yourself and see how easy it is to use the LinkRunner AT 4000 network cable tester. Click on the orange dots to explore.

Home Screen
LinkRunner 10G Home Screen

Home Screen

Without the right visibility, it's difficult to resolve problems that impact multiple devices and network segments. NetAlly's LinkRunner AT 4000 is an advanced cable and network tester for Multigigabit NBASE-T and fiber Ethernet networks. It features comprehensive network discovery and topology mapping with advanced diagnostics and problem detection for in-depth troubleshooting.

Using network discovery plus layer 2 and 3 path analysis, it provides full visibility to help resolve complex issues, while still providing the automated tests for moves, adds, and changes validation and troubleshooting that the LinkRunner AT family of testers is known for.



AutoTest is the most comprehensive testing application on the LinkRunner AT 4000. The app is fully customizable with savable test profiles and reusable Test Targets. Multiple profiles can be grouped allowing a single button press to validate connectivity on all VLANs. AutoTest results are automatically uploaded to the Link-Live platform after you claim your LinkRunner AT4000.

AutoTest allows engineers to transfer their knowledge of network configurations to the instrument, empowering frontline technicians to run tests against various wired VLANs and with minimal training. The result is a repeatable, documented test with shortened overall test times, which otherwise would not be possible with other test methods.

Multi-Gig Link Detection

Multi-Gig Link Validation

The Wired Link Test verifies link speed/duplex for 10/100 Mbps and 1 Gbps, with detection of NBASE-T and Multigigabit 2.5G, 5G, and 10 Gbps links.

Investment in Multi-Gig infrastructure is wasted if the cable plant cannot support the desired speed. But diagnosis of link “downshifting” is difficult, often leading to finger-pointing between cabling contractors and equipment vendors. LinkRunner AT 4000’s measurements on active links provides root-cause evidence when link speed issues occur.

VLAN ID and Analysis

VLAN Identification and Analysis

The LinkRunner AT 4000 AutoTest automatically identifies and lists VLANs supported by the connected switch port by analyzing the VLAN IDs of the traffic received. The LinkRunner AT 4000 continues to show the distribution of traffic by VLAN until another wired AutoTest has executed, or the link to the switch port is severed.

Proper VLAN configuration of switch ports has become important to the operation and security of the modern network so that various traffic can be properly isolated. The LinkRunner AT 4000 AutoTest provides the visibility and documentation of VLAN configuration of switch port automatically that makes this previously complex verification task simple.

Switch Visibility

Switch Visibility

The LinkRunner AT 4000 AutoTest automatically detects the nearest connected switch port by analyzing the xDP (CDP, LLDP, and EDP) protocols received. The LinkRunner AT 4000 reports the content of the first xDP packet received as the nearest switch in the AutoTest result. It continues to monitor the xDP traffic received and lists the source devices and the content of xDP traffic in the Switch Test detail.

The LinkRunner AT 4000 wired AutoTest provides quick visibility to the configuration of the nearest switch port connected in most cases. Even when it is connected to a switch that has the xDP traffic function disabled or set to be transmitted very infrequently, the LinkRunner AT 4000 can still provide visibility to the nearest xDP-supporting devices. There is no need to use a protocol analyzer to verify xDP configuration, which is much easier for network technicians to handle.

Switch Test

Switch Test

The Switch test provides a graphical representation of the immediate connection. The LinkRunner AT 4000 uses the IEEE Link Layer Discovery Protocol (LLDP), plus the Cisco and Extreme Discovery Protocols (CDP and EDP) to display the nearest switch name, chassis, model, slot, and port. Plus, displays other critical information like switch MAC/IP address, connected VLAN and VLANs supported, link speed and duplex (can identify advertised link speeds up to 10G), connection (MDI or MDI/X), and PoE voltage/power (actual and under TruePower™ load).

Quickly view switch information, such as name/port, detected link speed/duplex, and VLAN configuration. If PoE is enabled, test the power that the switch can offer under load, against what the switch advertises.

Cable Test

Cable Test

The LinkRunner AT 4000’s Cable Test can help you determine cable length and fault status, verify wire mapping of patch cords and structured cabling, and locate cables using toning or WireView office locators. Test structured cabling using the top RJ-45 port. Test patch cables with the built in second RJ-45 for complete pin to pin mapping and TDR.

Quickly identify cable faults like opens, shorts, or split pairs. You can also validate the wiremap, cable length, shield, or see if the other end of the cable is connected to a switch/station.



The Ping/TCP test app runs a Ping or TCP Connect test to your chosen target, allowing you to verify connectivity and identify intermittent issues.

A Ping test sends an ICMP echo request to the selected target to determine whether it can be reached and how long it takes to respond. Test for MTU issues using the frame size and do not fragment settings. The results are trended, displaying the last 24 hours as well as loss statistics.

A TCP Connect test opens a TCP connection with the selected target to test for port availability using a 3-way handshake (SYN, SYN/ACK, ACK). You can open the TCP/Ping app from the Home screen, or you can select Ping or TCP Connect from another app, such as AutoTest, while viewing a device’s details.

Continuous testing with response time measurements is available to verify consistency and identify intermittent issues. These tests can be easily recalled by field technicians to reduce configuration time or mistakes, to get more done faster.



The LinkRunner AT 4000’s Discovery application creates an inventory of the devices on your networks along with their attributes: device types, names, addresses, interfaces, VLANs, resources, and other connected or associated devices. The app allows you to identify and analyze network devices and acts as a jumping-off point for further analysis using other apps, such as Ping/TCP, Path Analysis, and connection tests.

Instantly see what is on the network and where it is connected, by switch, slot, and port number. Identify changes in connected devices and links, and quickly investigate and locate “suspect” devices and identify problems associated with device misconfigurations.

Path Analysis

Path Analysis

Path Analysis traces the connection points, including intermediate routers and switches, between the tester and a destination URL or IP address. You can use Path Analysis to identify issues such as overloaded interfaces, overloaded device resources, and interface errors. It also shows how devices within your network (and off-net devices) are connected to each other along a path including split routes.

LinkRunner AT 4000 has the unique ability to break through the “visibility ceiling” between wired networks, showing who and what is on your network, where they are connected, and their path across your network.



Packet capture is the process of recording network traffic in the form of packets as data streams back and forth over wired connections. Packet captures can help you analyze network problems, debug client/server communications, track applications and content, ensure that users are adhering to administration policies, and verify network security.

You can open the Capture app from the Home screen or using a link from another app, such as AutoTest or Discovery.

Having the power of 1G capture in the palm of your hand means you are always equipped to gather the evidence needed for in-depth troubleshooting and problem escalation.

Performance Reflector

Performance Reflector

The LinkRunner AT 4000 offers a packet reflector mode, which enables you to conduct end-to-end network performance tests when used with other NetAlly tools (LinkRunner 10G, EtherScope® nXG, CyberScope® CE). This mode validates network throughput capabilities up to 1Gbps. The reflector also works for 1G LANBERT™ media qualification testing. The line rate reflector supports control of what types of packets to reflect as well as swapping of source and destination MAC and IP addresses for L3 performance testing.

The Reflector app allows you to verify SLA of critical network links when deploying 1G links to support critical devices, e.g. servers, NAS, and WiFi access points, ensuring you’re getting the bandwidth you expect.



iPerf is a standardized network performance tool used to measure UDP or TCP throughput and loss. It is used to verify and ensure adequate client bandwidth is available.

The iPerf app verifies SLA of critical network links that support critical devices like servers, network-attached-storages, and WiFi access points, ensuring you are getting the bandwidth you expect.

"The LRAT AT 4000 has proven to be an exceptional addition to our toolbox. It has significantly reduced the time and cost associated with the troubleshooting process."

Paul S.

Engineer, Hallbeck IT

Discovery and Path Analysis are central to understanding and visualizing network layouts and performance bottlenecks in real-time:

  • Discovery: Catalogs all network-connected devices across multiple VLANs and subnets, gathering details on device types, names, addresses, and more. This provides a detailed view of the network setup and helps identify potential vulnerabilities.

  • Path Analysis: Evaluates the network path from the LinkRunner AT 4000 to a specific target, pinpointing any problematic segments or devices that may hinder network performance. This process provides a clear map of traffic flow and disruptions.

The LinkRunner AT 4000 is more than just a VLAN testing tool or smart network tester tool; it integrates AutoTest and Profiles with switch and cable testing functionalities to ensure all layers of the network infrastructure are thoroughly examined:

  • AutoTest: The network tester tool executes a series of network connectivity tests in a matter of seconds, verifying service availability, link speed, and network health — critical for operational reliability.
  • Switch Test: This feature collects extensive data on connected switches including configuration details and PoE statuses which are vital for resolving access layer issues swiftly.

  • Cable Test: As a network cable tester, the LinkRunner AT 4000 ensures the integrity of physical wiring within the network, testing for everything from correct termination to appropriate length and identifying any physical defects.

Network responsiveness and security are tested and verified through Ping/TCP testing and packet capture features, assisting technicians in maintaining optimal network operations:

  • Ping/TCP Test: This feature allows for quick verification of device reachability and network service availability, providing insights into network stability and performance.

  • Capture: Facilitates an in-depth analysis of traffic patterns and packet flows, crucial for troubleshooting complex network issues and ensuring security protocol compliance.

Performance testing is critical for any network changes or deployments, the Reflector and iPerf features provide robust capabilities in this regard:

  • Performance Reflector: Integrates with other NetAlly tools to perform end-to-end performance tests, ensuring network segments meet required speed standards.

  • iPerf: Effectively measures and validates network bandwidth, crucial for data-heavy applications, ensuring that every segment of the network can handle proposed load increases
Model Number/NameDescription
LRAT-40001G Advanced Ethernet Tester – includes: LinkRunner AT 4000 tester with 1 year of AllyCare support (LRAT-4000-1YS), Power Supply with regional power plugs, WireView Cable ID #1, RJ-45 coupler, 850nm multimode 1 Gbps SFP, Getting Started Guide and Shoulder Sling Bag.
LRAT-4000-KIT1G Advanced Ethernet Tester Professional Kit – includes: LinkRunner AT 4000 tester with 1 year of AllyCare support (LRAT-4000-1YS), Power Supply with regional power plugs, WireView Cable ID #1-#6, RJ-45 coupler, 850nm multimode 1 Gbps SFP, Holster, Getting Started Guide and Shoulder Sling Bag.
LINKSOLUTIONS-KT-4K1G Advanced Ethernet Tester Link Solutions Kit – includes: (1) LinkRunner AT 4000 tester with 1 year of AllyCare support (LRAT-4000-1YS), (1) Power Supply with regional power plugs, (1) WireView Cable ID #1, (1) RJ-45 coupler, (1) 850nm multimode 1 Gbps SFP, (1) Getting Started Guide, (1) Shoulder Sling Bag, (2) LinkSprinter network testers, (1) LinkRunner AT holster (HOLSTER-G3), and (2) LinkSprinter holsters.
G3-PWRADAPTERAC Charger replacement/spare for LRAT-4000 mainframe with country power cords.
HOLSTER-G3Field use carrying holster makes troubleshooting on the go easier. Openings allow access to all applicable buttons and interfaces. 
SFP-100FX100BASE-FX Fiber SFP transceiver with DDM (Multimode)
WIREVIEW 1WireView wire mapper #1
WIREVIEW 2-6WireView wire mapper #2-#6
ALLYSPACKSling-style shoulder bag can hold one tester and accessories, with other pouches and compartments for various tools or personal items
Testing Feature/AppAT 3000AT 400010G
AutoTest & Profiles
Switch Test
Cable Test
Ping/TCP Test
Performance Test Reflector
Performance Test Controller + Peer
Discovery/Topology Mapping (in Link-Live™)
Path Analysis
HTTP/FTP Response Time
Remote Visibility & Control*
WiFi Connectivity with Optional Adapter
Periodic AutoTest
Connect & Verify Link Speed/Duplex – 10M, 100M, 1G
Connect & Verify Link Speed/Duplex – Multi-Gig/NBASE-T/10G
Link Speed Detection – Multi-Gig, NBASE-T/10G
Integrated Camera, Microphone, and Micro SD Card
Included 1-Year AllyCare Premium SupportOptional
*Requires AllyCare Premium Support.


LinkRunner AT 4000 Product Datasheet


LinkRunner Product Comparison
LinkRunner AT Upgrade GuideDownload
NetAlly Product Selection Guide
AllyCare Premium Support Services Flyer


LinkRunner Family BrochureDownload
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LinkRunner AT 3000/4000 Quick Start Guide (English)
LinkRunner AT 3000/4000 User Guide (English)
Compliance and Safety (English)
Compliance and Safety (Multilingual)
Dimensions4.02 in x 7.72 in x 1.65 in (10.2 cm x 19.6 cm x 4.2 cm)
Weight1.06 lbs (0.48 kg)
BatteryRechargeable lithium-ion battery pack (3.63 V, 9.75 Ah, 36.39 Wh)
Battery lifeTypical run duration: 9 hours
Typical charge time: 3 hours
Display5.0-inch color LCD with capacitive touchscreen (720 x 1280 pixels)
Host InterfacesRJ-45 and SFP test port
RJ-45 Cable test port
(1) USB Type-A Port
(1) USB Type-C On-the-Go Port
SD Card PortSupports Micro SD card storage – up to 32GB supported
MemoryApproximately 8 GB available for storing test results and user applications
Battery ChargingUSB Type-C 45-W adapter: 100-240 Vac, 50-60 Hz; DC Output Power 15 V (3 A)
Media AccessCopper: 10M/100M/1G/2.5G/5G/10G
Fiber SFP Adapters: 1G/10GBASE-X
Supported IEEE StandardsWired: 802.3/ab/i/u/z, 1000BASE-T
PoE: 802.3af/at/bt Class 0-8, and UPOE
Fiber: 1000BASE-X, SFP SX/LX/ZX
LEDs1 LED (Battery Status Indicator)
Operating Temperature

32°F to 113°F (0°C to +45°C)

NOTE: The battery will not charge if the internal temperature of the tester is above 113°F (45°C)

Operating relative humidity (% RH without condensation)90% (50°F to 95°F; 10°C to 35°C)
75% (95°F to 113°F; 35°C to 45°C)
Storage Temperature-4°F to 140°F (-20°C to +60°C)
Shock and vibrationMeets the requirements of MIL-PRF-28800F for Class 3 Equipment
SafetyIEC 61010-1:2010: Pollution degree 2
AltitudeOperating: 4,000 m; Storage: 12,000 m
EMCIEC 61326-1: Basic Electromagnetic Environment
CISPR 11: Group 1, Class A

NOTE: All new LRAT-4000 mainframes are sold with the first year (1 year) of AllyCare support included. Additional year(s) of support may be added. Product registration and activation is required within 30 days of first power-on.

Certain features and capabilities of this product are enabled by having an active AllyCare Support services contract. For more information about this product’s AllyCare enabled features please click here. At the end of your existing contract, you must renew your AllyCare Support contract to continue utilizing the features described.

Use these support model numbers for extending support at time of purchase or for support renewal.

Model Number/NameDescription
LRAT-4000-1YSOne year of AllyCare support for LRAT-4000, LRAT-4000-KIT, and LINKSOLUTIONS-KT-4K (covers LRAT-4000 only).
LRAT-4000-2YSTwo years of AllyCare support for LRAT-4000, LRAT-4000-KIT, and LINKSOLUTIONS-KT-4K (covers LRAT-4000 only).
LRAT-4000-3YSThree years of AllyCare support for LRAT-4000, LRAT-4000-KIT, and LINKSOLUTIONS-KT-4K (covers LRAT-4000 only).