OSPF single-area 0 — auto-converging WAN: 8 devices connected by 7 links, 7 up. R-A (router), R-B (router), R-C (router), R-D (router), PC-A (pc), PC-B (pc), PC-C (pc), PC-D (pc).
Interactive network lab · beginner to advanced
NETFORGE-AI / BROWSER-BASED NETWORK SIMULATOR
Build real networks. See every packet move.
NetForge-AI is a browser-based network simulator and networking course. Drag in routers, switches, PCs and servers, configure them in an industry-standard CLI, and watch ARP, ICMP, DHCP and routing decisions travel the cables in real time.
- No install, no vendor account
- Free: 5-device lab + Module 1
- ARIA AI Agent with the Lab & AI Pass or All-Access Max
ARIA AI Agent
Describe a network. Watch ARIA build it.
Lab & AI Pass · All-Access MaxIn Agent Mode, ARIA drops the devices, types the CLI on each one, pings to verify, and fixes what fails — step by step, on your canvas. Included with the Lab & AI Pass and All-Access Max. The Free plan, the Lab Only Pass and the Course & Lab Pass don't include AI.
Animated demonstration: a student asks the ARIA AI Agent (included with the Lab & AI Pass and All-Access Max) to build a network topology in plain English. ARIA generates the devices and cables on the lab canvas, configures them, and verifies connectivity with a ping — looping through several example networks.
Features
Everything you need to actually understand a network. Not to memorise one.
No flashcards. NetForge-AI teaches by letting you build broken topologies and watch them fail — then fix them, hop by hop.
Drag and wire
Drop devices on an infinite canvas, drag a cable from one to another, and pick the port on each end. Serial and wireless ports choose their media automatically; switch a cable to fiber from its menu.
A workspace for every topology
Industry-standard CLI
A familiar EXEC, privileged, and config mode. hostname, interface, ip address, no shutdown, ip route, show running-config — all working.
Commands with visible outcomes
Live packet animation
Every ARP, ICMP, and DHCP frame is rendered as a glowing dot travelling the cable. See exactly which port floods and which forwards.
The network in motion
Routing you can follow
Connected, static, and default routes. Longest-prefix match, hop-by-hop tracing, TTL exhaustion, and routing-loop detection — all visualized.
From one hop to the whole journey
Switch fabric
MAC learning, flooding-vs-forwarding, VLAN tagging, broadcast domains, and ARP-resolved unicast paths.
What happens between ports
Keep your next idea
Save labs to your account, export and import them as JSON, and share a complete lab with classmates in one click. 17 example labs ship in-app.
Build. Experiment. Repeat.
How it works
Four steps. No setup, no licence, no download.
Anyone can build in the lab. A free account saves your work and opens Module 1 — no card.
- 01
Drop devices onto the canvas
Routers, L2/L3 switches, PCs, servers, hubs, access points, and a WAN cloud — each with realistic interface counts.
- 02
Wire devices by dragging
Drag from a device's edge dot onto another device, then choose the port on each end. Serial and wireless ports pick their media automatically.
- 03
Configure with GUI or CLI
Set IPs from the side panel, or drop into the device CLI: configure terminal, interface gi0/0, ip address …, no shutdown.
- 04
Run traffic and watch it travel
ping from any device. Frames animate across cables. ARP and MAC tables fill in. Routing decisions log live.
Your first ping is four steps away. Build without an account, or start free to save your work.
Protocol coverage
The OSI stack — visible, inspectable, and breakable.
Every protocol NetForge-AI implements is logged step by step, so you can see why a packet was dropped or which route was chosen.
Physical / L1
- Copper Ethernet
- Fiber
- Serial WAN
- Wireless 802.11
Data Link / L2
- MAC learning & aging
- VLANs (access/trunk)
- Spanning Tree (STP/RSTP/PVST+)
- EtherChannel (LACP/PAgP)
- ARP request/reply
Routing / L3
- IPv4 addressing & subnetting
- Static & default routes
- OSPF (DR/BDR, cost)
- EIGRP (bandwidth+delay metric)
- RIPv2
- BGP (eBGP & iBGP)
Services & security
- DHCP server pools
- VRRP first-hop redundancy
- NAT (static / pool / PAT)
- Standard & extended ACLs (L4 ports)
- ICMP echo / time-exceeded
Who it's for
Built by network engineers, for everyone learning.
Students learning networking
Work through an 8-module networking curriculum that takes you from beginner to advanced: 49 chapters, 115+ practice questions, hands-on labs, and a 60-question Final Weighted Exam. Module 1 is free; modules 2–8 come with the Course & Lab Pass or All-Access Max.
Instructors running labs
Save a topology, distribute the JSON, students load it locally. Give graded scenarios with broken configurations — let them fix it.
Engineers prototyping designs
Sketch an IP plan and validate routing logic in minutes. NetForge-AI is a fast, lightweight whiteboard for L2/L3 conversations.
FAQ
Questions people ask before they open the lab.
What is NetForge-AI?
NetForge-AI is a browser-based network simulator and networking course for learning routing, switching, and core IP protocols from beginner to advanced. Drag virtual routers, switches, and PCs onto a canvas, configure them with an industry-standard CLI, and watch packets animate across the topology in real time.
Is NetForge-AI a browser-based network simulator?
Yes. NetForge-AI covers the core networking topics learners practice — IP addressing, subnetting, VLANs, ARP, ICMP, static routing — and runs entirely in the browser. It is independently developed and not affiliated with any networking vendor or certification body.
Do I need to install anything?
No. NetForge-AI is a web app. Anyone can browse the course syllabus without an account; reading chapter content and saving labs requires a free account (no card needed); the lab itself is open to everyone.
Which protocols are simulated?
NetForge-AI simulates Layer 1 cabling (copper, fiber, serial, wireless), Layer 2 switching with MAC learning, VLANs and 802.1Q trunks, Spanning Tree Protocol (STP/RSTP/PVST+) with real root-bridge election, and EtherChannel (LACP/PAgP). At Layer 3 it runs IPv4 static and default routing plus four dynamic protocols — OSPF with DR/BDR election, EIGRP with the bandwidth-and-delay composite metric, RIPv2, and BGP (both eBGP and iBGP). It also models VRRP first-hop redundancy, NAT (static, dynamic pool, and PAT/overload), standard and extended ACLs with Layer 4 TCP/UDP port matching, ARP, ICMP, and DHCP server pools.
Can I save and share my topology?
Yes. Save keeps your full topology — devices, interfaces, IPs, routes, links — in your account, and Export downloads it as a JSON file. Anyone with NetForge-AI can open that file with Import, or you can hand out a read-only Share link.
Is this suitable for building real networking skills?
NetForge-AI covers core networking topics in switching and IPv4 routing, taking you from beginner to advanced. It is great on its own and pairs well with any study guide, giving you hands-on practice that mirrors real-world configuration tasks.
Does NetForge-AI cost anything?
You can start free. The Free plan (free account, no card) includes Module 1, a lab with up to 5 devices per topology and 3 saved topologies — and no AI. The Lab Only Pass ($15/mo or $129/yr) removes the lab limits. The Course & Lab Pass ($25/mo or $219/yr) adds all 8 modules, the Final Weighted Exam and the Verified Certificate. The Lab & AI Pass ($25/mo or $219/yr) removes the lab limits and adds the ARIA AI Agent, with Module 1 of the course. All-Access Max ($35/mo or $299/yr) includes everything, with ARIA in the lab and in every course chapter.
Does the free plan include AI?
No. The Free plan, the Lab Only Pass and the Course & Lab Pass don't include AI. ARIA AI is included with the Lab & AI Pass (in the lab) and All-Access Max (in the lab and in every course chapter).
What is the ARIA AI Agent?
ARIA is NetForge-AI's AI assistant. In the lab it answers questions about your topology. In Agent Mode it adds devices and cables, types the CLI on each device, runs pings to verify connectivity and diagnoses what fails. It's included with the Lab & AI Pass and All-Access Max, each with a monthly AI usage allowance.
Is ARIA unlimited?
No. Plans with ARIA include a monthly AI usage allowance that resets at 00:00 UTC on the 1st of each month, on monthly and yearly billing alike. Your account shows how much you've used as a percentage. All-Access Max includes 2× the allowance of the Lab & AI Pass. When the allowance is used up, ARIA pauses until the reset; the lab and course keep working.
Course & Lab Pass or Lab & AI Pass?
They cost the same but include different things. The Course & Lab Pass is for the course: all 8 modules, the Final Weighted Exam and the Verified Certificate, with no AI. The Lab & AI Pass is for building: it adds the ARIA AI Agent to the lab and includes Module 1 of the course. Both remove the Free plan's device and save limits. All-Access Max has everything.
What does "unlimited lab" mean?
No plan-based limit on devices per topology or on saved topologies. The same technical limits apply on every plan: a topology can be saved, shared or imported with up to 1,000 devices and 4,000 cables, a saved topology can be about 500 KB, and you can have 50 active share links.
Ready when you are
Stop reading about networks. Start building them.
Start free to save your labs and open Module 1 — no card required. Or jump into the lab and build without an account.