Pause4Tech — Lab Setup Master Guide | From Zero to Working Lab

1

Understand the Big Picture

Why you need three layers to build a professional network lab

Foundation

Before touching any software, understand what you are building. A network lab has three layers:

Layer	What It Is	Real-World Analogy
Layer 1: Hypervisor	Software (VMware or VirtualBox) that runs virtual machines on your PC	The foundation of a building
Layer 2: EVE-NG	A Linux virtual machine that emulates Cisco network devices	The office floors on the foundation
Layer 3: .unl + Images	Topology files and Cisco IOS images that become your routers	The furniture inside the office

💡 The Complete Flow

Your PC → VMware / VirtualBox → EVE-NG Linux VM → Cisco Images → .unl Topology File → Live Working Lab

What You Will Have at the End

✅ A fully functional EVE-NG server running on your PC
✅ Cisco routers and switches emulated in software
✅ Any Pause4Tech .unl file loaded and running
✅ Ability to build your own topologies from scratch
✅ Internet access from within lab devices (optional)

Time & Resource Expectations

Task	Time	Difficulty
Install hypervisor	15 min	⭐ Easy
Install EVE-NG	30 min	⭐⭐ Easy-Moderate
Configure network	15 min	⭐⭐ Easy-Moderate
Import Cisco images	20 min	⭐⭐⭐ Moderate
Import first .unl file	5 min	⭐ Easy
Total First-Time Setup	~1.5 hours	—

2

Choose & Install Your Hypervisor

VMware Workstation Player vs Oracle VirtualBox

Step 1

System Requirements (Minimum)

Component	Minimum	Recommended
CPU	4 cores with Intel VT-x / AMD-V	8+ cores
RAM	8 GB	16 GB or more
Storage	80 GB free	250 GB SSD
OS	Windows 10, Ubuntu 20.04+	Windows 11, Ubuntu 22.04+

Which Hypervisor Should You Use?

Your Setup	Recommended Choice
Windows PC, beginner	VMware Workstation Player
Linux PC (Ubuntu, Fedora)	Oracle VirtualBox
Mac (Intel chip)	VMware Fusion
Mac (Apple Silicon M1/M2/M3)	UTM (EVE-NG support is limited)

Option A — Install VMware Workstation Player (Windows)

1Enable Virtualization in BIOS

Restart your PC. Press F2, DEL, F10, or ESC during boot to enter BIOS/UEFI. Find Intel VT-x or AMD-V, enable it, save and exit.

2Download VMware Workstation Player

Visit the official download page: VMware Workstation Player. Download the Windows installer (free for personal use).

3Install VMware Workstation Player

Double-click the installer and accept the license agreement
Choose a destination folder (default is fine)
Select "Enhanced Keyboard Driver" and "Add to PATH" (recommended)
Click Install → wait → click Finish

Option B — Install Oracle VirtualBox (Windows / Linux)

1Download VirtualBox + Extension Pack

Visit the official downloads page: Oracle VirtualBox Downloads. Download the version for your OS AND the matching Extension Pack (same version number).

2Install on Windows

Run the installer → Next through the wizard
Accept warnings about network interfaces (this is normal)
Click Install → wait → Finish

3Install on Ubuntu / Linux

sudo apt update
sudo apt install virtualbox virtualbox-ext-pack

💡 Verify Your Hypervisor Works

Open the hypervisor and confirm you see the "Create New Virtual Machine" option. If you see a virtualization error, return to Step 1 and check BIOS settings.

3

Install EVE-NG (Community Edition)

Deploy EVE-NG as a virtual machine inside your hypervisor

Step 2

Download EVE-NG

Visit the official EVE-NG download page: EVE-NG Community Edition Download
Download the Community Edition ISO (about 1 GB)
Also download the EVE-NG Client Pack from the same page (EVE-NG Client Pack) — you will need this for console access

Create the EVE-NG Virtual Machine

1Open VMware Workstation Player → Create New VM

Select "Installer disc image file (ISO)"
Browse to the EVE-NG ISO you downloaded

2Choose Guest OS

Guest OS: Linux
Version: Ubuntu 64-bit

3Name and Location

VM Name: EVE-NG
Location: A folder on your SSD (avoid external drives)

4Processor Configuration

Number of processors: 2
Number of cores per processor: 4
Total = 8 cores (adjust based on your CPU)

5Memory Configuration

Allocate 8 GB minimum, 16 GB recommended
Do not exceed 50% of your host RAM

6Network Type

Select NAT (Recommended)
NAT lets your host PC reach EVE-NG and EVE-NG reach the internet

7Disk Size

Set to 200 GB
Choose "Store virtual disk as a single file"
Enable "Split virtual disk into multiple files" only if storing on FAT32

8Click Finish

Review settings and click Finish. The VM will be created but NOT started yet.

Enable Nested Virtualization (Critical!)

⚠️ This step is mandatory

Without nested virtualization, your lab devices will not boot or will run extremely slowly. EVE-NG's official docs highlight this as the #1 setup failure.

9Enable VT-x / EPT in VM Settings

Right-click the EVE-NG VM → Settings
Go to Processors
Check "Virtualize Intel VT-x / EPT or AMD-V / RVI"
Also check "Virtualize CPU performance counters"
Click OK

Install EVE-NG

10Boot and Install

Click Play to start the VM
Follow the on-screen installer prompts
Set the root password (default: eve)
Set the hostname (e.g., eve-ng)
Choose DHCP for the management interface
After install, the VM will reboot and show you its IP address

💡 Note the IP Address

After installation, EVE-NG will display its management IP (e.g., 192.168.100.128). Write it down — you will use it to access the web console.

4

Configure Network Connectivity

Get your host, EVE-NG, and lab devices talking to each other

Step 3

Understanding Network Modes

Mode	What It Does	Use Case
NAT	VM shares host's internet, host can reach VM	Recommended for most setups
Bridged	VM appears as a separate device on your LAN	Access lab from other PCs on your network
Host-Only	Isolated network between host and VM only	Security-focused isolated labs

Recommended Setup: NAT + Host-Only Combo

For professional lab use, add a second network adapter to your EVE-NG VM:

1Add Second Network Adapter

Shut down the EVE-NG VM
Right-click VM → Settings → Add → Network Adapter
Set adapter 1: NAT (for management + internet)
Set adapter 2: Host-Only (for isolated lab traffic if needed)
Click OK

Verifying Internet Access from Lab

2Test Connectivity

SSH into EVE-NG: ssh root@<EVE-NG-IP> (password: what you set)
Test internet: ping -c 4 8.8.8.8
If you get replies → network is working
If not → check that your host PC has internet and NAT is configured correctly

⚠️ Common Mistake

Do NOT set the second adapter to Bridged unless you know what you're doing. Bridged mode causes IP conflicts and DHCP issues in many home networks.

5

Access the EVE-NG Web Console

Log in and explore the interface

Step 4

1Open the Web Interface

On your host PC, open a browser and go to:

http://<EVE-NG-IP>

Replace <EVE-NG-IP> with the IP you noted in Part 3.

2Login

Username	`admin`
Password	`eve` (default)

3Familiarize Yourself with the Interface

Left panel — Folders and labs
Center canvas — Where you build topologies
Top toolbar — Add nodes, connections, start/stop
Right panel — Details of selected node

💡 Install the EVE-NG Client Pack

For console access to lab devices, download and install the EVE-NG Client Pack. This enables Telnet/SSH/RDP console connections from your host.

6

Import Pause4Tech .unl Files

The most important section: from a downloaded file to a working lab

Step 5 · Critical

Your Pause4Tech modules include ready-made .unl files — these are topology files that EVE-NG can open directly. When you import a .unl file, all routers, switches, links, and configurations are pre-built for you. All you have to do is turn the lab on and start practicing.

💡 What is a .unl File?

A .unl file is a compressed archive containing: (1) the topology map, (2) all devices and their positions, (3) the links between them, and (4) any starting configuration files. You don't need to understand its internals — you just upload it to EVE-NG.

Step 1 — Download the .unl File

1From the Pause4Tech Lab Guide

Open the relevant Lab Guide page on Pause4Tech (e.g., EIGRP Module A Lab Guide)
Scroll to the "Download Lab Package" section
Click the download link for the .unl file (e.g., EIGRP_A_Lab1_Basic.unl)
The file will download to your PC's default Downloads folder

💡 What You Should See

The downloaded file should look like EIGRP_A_Lab1_Basic.unl (approximately 5–20 KB in size). Do NOT try to open it with any application — it's a file specifically for EVE-NG.

Step 2 — Understand the Upload Methods (Choose One)

There are three ways to upload a .unl file to EVE-NG. Choose the one that fits your skill level:

Method	Difficulty	Best For
A. Web GUI Import	⭐ Easy	Beginners (Recommended)
B. SFTP via WinSCP	⭐⭐ Moderate	Users familiar with file transfer tools
C. SCP Command Line	⭐⭐⭐ Advanced	Linux/Mac users, automation

Method A — Web GUI Import (Recommended for Beginners)

A1Log in to EVE-NG

Open your browser
Navigate to: http://<EVE-NG-IP>
Login with: username admin, password eve

A2Navigate to Import Location

Look at the left sidebar in EVE-NG
You will see a folder structure like Labs/
Click on the folder where you want the lab to appear (e.g., the root folder)

A3Import the .unl File

Look at the top toolbar and find the icon that looks like an upload arrow or "Import"
Click it → a file dialog opens
Browse to your Downloads folder
Select the .unl file (e.g., EIGRP_A_Lab1_Basic.unl)
Click Open

The file uploads in a few seconds. A green notification will confirm the import was successful.

A4Open the Lab

In the left sidebar, find your newly imported lab (the name matches the .unl filename, minus the extension)
Double-click it to open
The canvas will display the topology from the .unl file — routers, switches, links all visible

Method B — SFTP via WinSCP (Alternative)

B1Download and Install WinSCP

Visit: WinSCP Download Page
Download the portable or installer version
Install WinSCP

B2Connect to EVE-NG

Open WinSCP
Fill in the connection details:

File Protocol	`SFTP`
Host Name	Your EVE-NG IP (e.g., `192.168.100.128`)
Port Number	`22`
Username	`root`
Password	Whatever you set during install (default: `eve`)

Click Login. Accept the SSH key if prompted.

B3Upload the .unl File

On the left panel (your PC), navigate to the Downloads folder
On the right panel (EVE-NG), navigate to: /opt/unetlab/labs/
Drag the .unl file from left to right
Wait for the upload to complete

B4Fix Permissions (Required)

Open an SSH session to EVE-NG and run:

/opt/unetlab/wrappers/unl_wrapper -a fixpermissions

This ensures EVE-NG can read the newly uploaded file.

Method C — SCP Command Line (Advanced)

C1From Linux / macOS Terminal

scp ~/Downloads/EIGRP_A_Lab1_Basic.unl root@<EVE-NG-IP>:/opt/unetlab/labs/

# Then SSH in and fix permissions
ssh root@<EVE-NG-IP>
/opt/unetlab/wrappers/unl_wrapper -a fixpermissions

C2From Windows PowerShell

scp C:\Users\YourName\Downloads\EIGRP_A_Lab1_Basic.unl root@<EVE-NG-IP>:/opt/unetlab/labs/

Step 3 — Start the Lab Devices

1Open the Lab Canvas

After import, the topology is loaded but all devices are OFF. You will see grey dots above each device indicating they are stopped.

2Start All Devices

Click somewhere on the canvas to deselect any device
On the top toolbar, find the green triangle (Play icon)
Click it → select "Start all nodes"
Wait 30–60 seconds for all devices to boot

3Verify Devices Are Running

🟢 Green dot above device = running
⚫ Grey dot = stopped
🟠 Orange dot = booting (wait a bit longer)

Step 4 — Access Your First Device Console

1Open a Console

Click on any router in the topology
Right-click → Console → choose HTML5 (recommended) or Telnet
A terminal window will open showing the device's CLI

2Verify Access

Router> enable
Router# show ip interface brief
Router# show version

If you see output, your lab is working! You are now ready to follow the Pause4Tech Lab Guide tasks.

Step 5 — Start the Actual Lab Exercise

💡 Now Go Back to the Lab Guide

With your .unl file loaded and devices running, return to the Pause4Tech Lab Guide page and start Task 1. The lab guide assumes you have a working topology like the one you just imported.

Troubleshooting .unl Import

Problem	Cause	Fix
File won't upload in Web GUI	Browser cache / session issue	Clear browser cache, log out, log back in, retry
Lab shows but devices won't start	Cisco images not imported	Proceed to Part 7 — Add Cisco Images
"Error: missing image"	The .unl references an image you don't have	Import the exact image name listed in the error
Console window doesn't open	EVE-NG Client Pack not installed	Install the EVE-NG Client Pack
Devices boot but show no config	The .unl requires initial config	Paste the startup config from the Lab Guide into each device

⚠️ If Nothing Works

Do not assume the .unl file is broken. 95% of import failures are due to: (1) missing Cisco images, (2) permission issues on the EVE-NG server, or (3) EVE-NG version mismatch. Work through Part 7 (Add Cisco Images) first, then retry the import.

7

Add Cisco Images to EVE-NG

Download, upload, and enable Cisco router/switch images

Step 6 · Most Detailed

EVE-NG does not ship with Cisco images. You must supply your own. Without images, your topology will load but devices will not boot. This is the second most common beginner blocker (after nested virtualization).

Image Types Explained

Type	Best For	Typical File Size	Difficulty
IOL (IOS on Linux)	CCNA/CCNP Routing & Switching labs	~15–25 MB	⭐ Easy (Recommended)
Dynamips	Legacy IOS (real Cisco hardware emulation)	~80–200 MB	⭐⭐ Moderate
QEMU	IOSv, IOS-XE, ASAv, Nexus (modern images)	~500 MB – 2 GB	⭐⭐⭐ Advanced

💡 Which One Do You Need?

For Pause4Tech labs (routing, switching, EIGRP, OSPF, BGP, VLANs), IOL images are all you need. They are tiny, fast, and perfectly emulate Cisco IOS. QEMU images are only needed for advanced labs (SD-WAN, firewall, Nexus).

Where to Get Cisco Images

⚠️ Legal Note

Cisco IOS images are copyrighted. You may legally download them only if you have a Cisco account with entitlement (e.g., an active support contract or valid CCO account with image access). Pause4Tech does not host or distribute Cisco images.

Legal sources:

Cisco official support portal — with a valid Smart Net contract
Cisco Learning Network — free images available for students enrolled in Cisco courses
Cisco DevNet — virtual images for developers
Your employer's Cisco account (if you work in networking)

Community note: Many engineers acquire images from EVE-NG community forums or the EVE-NG Team's recommended sources. Always ensure you comply with Cisco's licensing terms.

Recommended IOL Images for Pause4Tech Labs

Lab Type	Recommended IOL Image
Routing (EIGRP, OSPF, BGP)	`L3-ADVENTERPRISEK9-M-15.5-2T.bin`
Switching (VLANs, STP, VTP)	`L2-ADVENTERPRISEK9-M-15.2-IRON.bin`
Combined L2+L3	`L2-ADVENTERPRISEK9-M-15.2-IRON.bin` (supports both with `ip routing`)

How to Upload IOL Images

1Understand the Folder Structure

EVE-NG stores different image types in specific folders:

/opt/unetlab/addons/
├── iol/
│   └── bin/          ← IOL .bin files go here
├── dynamips/         ← Dynamips .image files
└── qemu/             ← QEMU .qcow2 files

2Connect via SFTP (WinSCP) or SCP

Use the same connection method from Part 6 (WinSCP or SCP):

Protocol	`SFTP`
Host	Your EVE-NG IP
Port	`22`
Username	`root`
Password	Your root password

3Copy Images to the Correct Folder

Via WinSCP:

Navigate to: /opt/unetlab/addons/iol/bin/
Drag your .bin files from your PC to this folder

Via SCP (Linux/Mac/Windows PowerShell):

scp L3-ADVENTERPRISEK9-M-15.5-2T.bin root@<EVE-NG-IP>:/opt/unetlab/addons/iol/bin/

4Verify the Files Are in Place

Open an SSH session and list the folder:

ssh root@<EVE-NG-IP>
ls -la /opt/unetlab/addons/iol/bin/

You should see your .bin files listed.

5Fix Permissions (Mandatory)

EVE-NG requires specific file permissions to load images:

chmod 777 /opt/unetlab/addons/iol/bin/*.bin
/opt/unetlab/wrappers/unl_wrapper -a fixpermissions

This is the #1 cause of "image not showing" errors.

6Reboot the EVE-NG VM

Log out and reboot EVE-NG:

reboot

Wait 60 seconds for the system to restart.

7Verify Images Are Available

Log back into the EVE-NG web console
Right-click on the canvas → Add Node
In the "Node Type" dropdown, select IOL
You should see your uploaded images in the "Image" dropdown

Uploading QEMU Images (Advanced)

QEMU images (IOSv, ASAv, IOS-XE, Nexus) require a different process:

1Create a Vendor Folder

Each QEMU image needs its own folder with a specific naming convention:

mkdir -p /opt/unetlab/addons/qemu/cisco-iosv-15.6

Folder naming rules: vendor-platform-version (all lowercase, hyphens instead of spaces).

2Upload the Image Files

Each QEMU image requires two files:

virtioa.qcow2 — the actual disk image
hda.qcow2 (or similar) — a secondary file for some images

Upload via WinSCP or SCP into the folder you created.

3Fix Permissions and Reboot

chmod -R 755 /opt/unetlab/addons/qemu/cisco-iosv-15.6/
/opt/unetlab/wrappers/unl_wrapper -a fixpermissions
reboot

Verifying Image Integration

Check	Command / Action	Expected Result
Files present	`ls -la /opt/unetlab/addons/iol/bin/`	Lists your .bin files
Permissions	`ls -la` (check -rwxrwxrwx)	Full permission on files
Images visible in GUI	Add Node → IOL	Image dropdown shows your files
Device boots	Start node → Open console	Router boots to CLI prompt

Troubleshooting Cisco Image Upload

Problem	Cause	Fix
Image not showing in Add Node dropdown	Wrong folder or permissions	Verify path and run `chmod 777` + `fixpermissions`
Device fails to boot	Nested virtualization disabled	Enable VT-x/EPT in VM settings (Part 3 Step 9)
"Permission denied" during upload	SFTP login used non-root user	Use `root` user with correct password
Image boots but no config	This is normal — .unl file will apply config	Not an error
Upload fails at 100%	Insufficient disk space in EVE-NG	Run `df -h` to check space, expand VM disk if needed

💡 Beginner Shortcut

If you are only doing Pause4Tech labs (routing, switching, EIGRP, OSPF, BGP), you can safely ignore QEMU and Dynamips images for now. Two IOL files are enough to complete every lab in the entire Pause4Tech library.

8

Verify & Test Your Lab

Confirm every layer is working before running the actual lab tasks

Step 7

Before you start any Pause4Tech lab, run through this 5-point verification checklist. It catches 90% of setup problems before they waste your time.

✅ 5-Point Pre-Lab Verification Checklist

#	What to Check	How to Verify	Expected Result
1	EVE-NG web console is reachable	Open browser → `http://<EVE-NG-IP>`	Login page appears
2	.unl file is imported	Left sidebar → find your lab name	Lab appears in the list
3	All devices have green status dots	Open the lab → look above each node	All dots are 🟢 green
4	Console access works	Right-click any device → Console → HTML5	Terminal window opens with CLI prompt
5	Images are correct	`show version` on each router	IOS version matches the lab requirement

Testing Connectivity Between Lab Devices

1Verify Interface Status

On any router, run:

enable
show ip interface brief

You should see interfaces in up/up state. If you see admin down or down/down, they may need to be enabled with no shutdown.

2Test Point-to-Point Reachability

From Router 1, ping Router 2's directly connected interface:

ping 10.1.12.2

If you get !!!!!, Layer 3 connectivity is working.

3Test Routing Protocol Adjacency

If the lab requires EIGRP/OSPF/BGP, verify adjacency:

show ip eigrp neighbors       ! For EIGRP labs
show ip ospf neighbor          ! For OSPF labs
show ip bgp summary            ! For BGP labs

You should see neighbor relationships in the appropriate state.

Verify Internet Access from a Lab Device

4Test Internet from a Router

Ensure the lab's edge router has a route to the internet (default route via Cloud0)
From the router CLI:

ping 8.8.8.8
ping google.com

If !!!!! succeeds for both, your lab has full internet access.

⚠️ If Internet Doesn't Work

Check that (1) Cloud0 is connected to the second network adapter, (2) the router has a default route, and (3) NAT is enabled on the host adapter — not Bridged.

Green Lights — You're Ready

🎯 You Are Now Lab-Ready

If all 5 verification points pass, your lab environment is fully operational. Return to the Pause4Tech Lab Guide and start Task 1 with confidence.

9

Start Your First Lab

A complete walkthrough of your first Pause4Tech lab exercise

Step 8

Let's walk through the entire process using EIGRP Module A — Lab 1 (Basic) as an example. The same workflow applies to every Pause4Tech lab.

Step 1 — Locate the Lab in the Module

1Navigate to the Lab Guide

From the Pause4Tech home page, click EIGRP Master Series
Click EIGRP Module A in the module hub
In the module hub, click Part 4 — Lab Guide

Step 2 — Download the Lab Package

2Get the .unl File

On the Lab Guide page, find the Download Lab Package section
Click EIGRP_A_Lab1_Basic.unl to download
The file saves to your Downloads folder

Step 3 — Import and Start the Lab

3Upload to EVE-NG

Follow the same steps from Part 6 (Method A):

Log in to EVE-NG web console
Click the import/upload icon
Select EIGRP_A_Lab1_Basic.unl
Wait for the success notification
Double-click the lab in the sidebar to open it

4Start All Devices

Click somewhere empty on the canvas
Click the Play (green triangle) icon in the toolbar
Select "Start all nodes"
Wait 45–60 seconds for devices to boot
Confirm all dots above devices turn green

Step 4 — Access Each Device Console

5Open Consoles for All Routers

Right-click on Router 1 → Console → HTML5
Repeat for Router 2, Router 3, and so on
Arrange the console windows so you can see multiple at once

Step 5 — Execute the Lab Tasks

6Follow the Lab Guide Task-by-Task

Return to the Lab Guide page and start at Task 1. For each task:

Read the objective
Type the commands shown in the Solution block
Run the verification commands
Compare your output with the Expected Output block
Move to the next task

Step 6 — Save Your Work

💡 Save Configurations Before Shutdown

On each router console, run write memory or copy running-config startup-config before stopping the lab. This preserves your work.

Recommended Learning Path

Order	Lab	Difficulty	Time
1	EIGRP_A_Lab1_Basic.unl — Basic config	⭐ Basic	20 min
2	EIGRP_A_Lab2_StaticNeighbor.unl — Static & dynamic	⭐⭐ Basic+	30 min
3	EIGRP_A_Lab3_Timers.unl — RTP & timers	⭐⭐⭐ Intermediate	35 min
4	EIGRP_A_Lab4_Scenario.unl — Failure simulation	⭐⭐⭐⭐ Advanced	40 min
5	EIGRP_A_Lab5_Challenge.unl — Multi-issue scenario	⭐⭐⭐⭐⭐ Expert	60 min

💡 Progress in Order

Always complete the labs in the order shown. Each lab builds on skills from the previous one. Skipping labs leads to gaps in understanding.

10

Troubleshooting & Fixes

The master reference for solving every common setup problem

Reference

This is the master troubleshooting reference. Bookmark this section — you will come back to it whenever something breaks.

Category 1 — Hypervisor Issues

Error	Cause	Fix
"VT-x is disabled"	Virtualization disabled in BIOS	Enter BIOS → enable Intel VT-x / AMD-V
VM won't start	Hyper-V or WSL2 conflicting on Windows	Disable Hyper-V: `bcdedit /set hypervisorlaunchtype off`, then reboot
Slow performance	Insufficient RAM or CPU cores	Increase VM memory to 8 GB minimum

Category 2 — EVE-NG Installation Issues

Error	Cause	Fix
EVE-NG won't boot	Nested virtualization not enabled	VM Settings → Processors → Check "Virtualize Intel VT-x / EPT"
Cannot reach web console	Network adapter misconfigured	Verify NAT adapter is enabled and firewall isn't blocking port 80
Cannot login (admin/eve)	Password changed during install	Use the password you set during installation

Category 3 — Network Configuration Issues

Error	Cause	Fix
No internet in lab devices	Cloud0 not connected or NAT disabled	Add Cloud0 to topology, verify adapter 2 is NAT (not Bridged)
IP conflicts on host network	Bridged mode conflicting with home LAN	Switch to NAT mode
Cannot ping between lab devices	Interface shut down or wrong IP	Run `no shutdown` and verify IPs with `show ip int brief`

Category 4 — .unl File Import Issues

Error	Cause	Fix
File won't upload in GUI	Browser cache or session issue	Clear cache, logout, login, retry
Lab imported but empty	Corrupted file or incomplete upload	Re-download .unl, retry upload
Devices show "missing image"	Cisco images not imported	Complete Part 7 — Add Cisco Images
Permissions error on import	Incorrect file permissions	Run `/opt/unetlab/wrappers/unl_wrapper -a fixpermissions`

Category 5 — Cisco Image Issues

Error	Cause	Fix
Image not visible in dropdown	Wrong folder or file permissions	`chmod 777 /opt/unetlab/addons/iol/bin/*.bin` then `fixpermissions`
"Permission denied" on SFTP upload	Non-root user	Log in as `root` with the correct password
Device boots but hangs at prompt	Image incompatibility	Try a different IOL image version
Upload fails at 100%	Disk space full	Run `df -h`, expand VM disk if needed

Category 6 — Console Access Issues

Error	Cause	Fix
Console window won't open	EVE-NG Client Pack not installed	Install EVE-NG Client Pack
Console opens but is blank	Device still booting	Wait 30–60 seconds, then press Enter
Console disconnects constantly	Browser or network issue	Try HTML5 console instead of Telnet

Category 7 — Performance & Resource Issues

Error	Cause	Fix
Lab devices run very slowly	Insufficient CPU/RAM	Increase VM resources in hypervisor settings
Host PC slows down	Too many lab devices running	Start only the devices needed for the current lab
EVE-NG crashes	Out of memory	Reduce devices or increase RAM allocation

💡 The Golden Rule of Troubleshooting

When something doesn't work, verify in this order: (1) Hypervisor — is the VM running and configured correctly? (2) Network — can your PC reach EVE-NG's web console? (3) Images — are the correct images imported? (4) .unl — is the lab file imported and does it reference available images? (5) Config — are the device configurations applied correctly?

🎉 You're Ready to Practice

Your full network lab environment is operational. Every Pause4Tech lab is now accessible — complete them in order, and you will master enterprise networking from the ground up.

🏠 Return to Home

From Zero to a Working Network Lab