VMware & Enterprise Networking Cheat Sheet
1. Small VMware Lab Network
A simple cybersecurity lab can use two isolated networks:
| Network | Type | Subnet | Purpose |
|---|---|---|---|
| Vulnerable | Host-only | 10.50.20.0/24 | CTF / vulnerable machines |
| NAT | NAT | 192.168.150.0/24 | Internet access |
2. Vulnerable Network
Network: 10.50.20.0/24
Subnet Mask: 255.255.255.0
DHCP: 10.50.20.1 – 10.50.20.10
Gateway: None
DHCP automatically assigns addresses:
10.50.20.1
10.50.20.2
10.50.20.3
...
10.50.20.10
Typical uses:
- CTF machines
- Vulnerable VMs
- Deliberately vulnerable applications
- Isolated pentesting targets
3. NAT Network
Network: 192.168.150.0/24
Subnet Mask: 255.255.255.0
NAT Gateway: 192.168.150.2
Static range
192.168.150.120 – 192.168.150.131
Example:
192.168.150.120 → Windows Server
192.168.150.121 → Ubuntu Server
192.168.150.122 → Static VM
192.168.150.123 → Static VM
...
192.168.150.131 → Static VM
DHCP range
192.168.150.132 – 192.168.150.145
Other VMs can receive addresses automatically from the DHCP pool.
Important rule
Static addresses and the DHCP pool must not overlap.
STATIC DHCP
────── ────
.120 .132
.121 .133
.122 .134
.123 .135
... ...
.131 .145
4. Windows — Static IP
Navigate to:
Network Connections → Adapter → Properties → IPv4
Select:
Use the following IP address
Example:
IP address: 192.168.150.120
Subnet mask: 255.255.255.0
Default gateway: 192.168.150.2
Preferred DNS: 192.168.150.2
Alternate DNS: blank
Verify:
ipconfig
5. Windows — DHCP
For automatic addressing:
Obtain an IP address automatically
Obtain DNS server address automatically
The VMware DHCP server assigns an address from its configured pool.
6. Ubuntu Server — Static IP
Ubuntu Server commonly uses Netplan.
Example interface:
ens33
Example Netplan configuration:
network:
version: 2
ethernets:
ens33:
dhcp4: false
dhcp6: false
addresses:
- 192.168.150.121/24
routes:
- to: default
via: 192.168.150.2
nameservers:
addresses:
- 192.168.150.2
Typical configuration file:
/etc/netplan/00-installer-config.yaml
Edit:
sudo nano /etc/netplan/00-installer-config.yaml
Apply:
sudo netplan apply
A reboot is normally not required.
Verify:
ip a
ip route
Expected:
192.168.150.121/24
and:
default via 192.168.150.2 dev ens33
Connectivity tests:
ping -c 4 192.168.150.2
ping -c 4 8.8.8.8
ping -c 4 google.com
7. Two-NIC VM
A VM that requires both an isolated lab network and Internet can use two network adapters:
VM
│
┌───────┴───────┐
│ │
NIC 1 NIC 2
│ │
Host-only NAT
│ │
10.50.20.x 192.168.150.x
Isolated/Lab NIC
IP: 10.50.20.5
Mask: 255.255.255.0
Gateway: blank
NAT NIC
IP: 192.168.150.120
Mask: 255.255.255.0
Gateway: 192.168.150.2
Routing rule
Normally, only the interface connected to the Internet-facing/NAT network should have a default gateway.
8. IP Allocation Design
A simple lab can separate static and dynamic addresses:
========================================
VULNERABLE NETWORK
========================================
Subnet: 10.50.20.0/24
DHCP: 10.50.20.1 – 10.50.20.10
Gateway: None
========================================
NAT NETWORK
========================================
Subnet: 192.168.150.0/24
Gateway: 192.168.150.2
STATIC:
.120 – .131
DHCP:
.132 – .145
9. What Is Subnetting?
Subnetting means dividing a larger IP network into smaller networks.
Example:
10.50.0.0/16
can be divided into:
10.50.10.0/24
10.50.20.0/24
10.50.30.0/24
10.50.40.0/24
Each subnet represents a separate IP network.
10. Realistic Enterprise Network
A company with approximately 100–200 devices might segment the environment using VLANs and different subnets:
| VLAN | Network | Subnet | Typical Use |
|---|---|---|---|
| 10 | Corporate | 10.60.10.0/24 | Employee devices |
| 20 | Servers | 10.60.20.0/27 | AD, DNS, application servers |
| 30 | Security | 10.60.30.0/27 | Pentest/security systems |
| 40 | CTF/Lab | 10.60.40.0/26 | Security testing |
| 50 | Management | 10.60.50.0/28 | Network infrastructure |
| 60 | Guest | 10.60.60.0/26 | Guest Wi-Fi |
| 70 | IoT | 10.60.70.0/27 | IoT devices |
This combines:
VLANs + subnetting + routing + firewall/ACL policies.
11. Common Subnet Sizes
| CIDR | Subnet Mask | Total IPs | Traditional Usable Hosts |
|---|---|---|---|
/24 | 255.255.255.0 | 256 | 254 |
/25 | 255.255.255.128 | 128 | 126 |
/26 | 255.255.255.192 | 64 | 62 |
/27 | 255.255.255.224 | 32 | 30 |
/28 | 255.255.255.240 | 16 | 14 |
/29 | 255.255.255.248 | 8 | 6 |
/30 | 255.255.255.252 | 4 | 2 |
12. /24 → /26 Subnetting Example
Starting network:
192.168.50.0/24
Divide it into four /26 networks:
192.168.50.0/26
192.168.50.64/26
192.168.50.128/26
192.168.50.192/26
Subnet 1
Network: 192.168.50.0
Usable: 192.168.50.1 – 62
Broadcast: 192.168.50.63
Subnet 2
Network: 192.168.50.64
Usable: 192.168.50.65 – 126
Broadcast: 192.168.50.127
Subnet 3
Network: 192.168.50.128
Usable: 192.168.50.129 – 190
Broadcast: 192.168.50.191
Subnet 4
Network: 192.168.50.192
Usable: 192.168.50.193 – 254
Broadcast: 192.168.50.255
13. Subnetting vs DHCP vs Static IP
These are different concepts:
SUBNETTING
↓
Divides networks
Example:
10.60.10.0/24
10.60.20.0/24
10.60.30.0/24
DHCP
↓
Automatically assigns IP addresses
Example:
10.60.20.100 – 10.60.20.200
STATIC IP
↓
Manually assigns a fixed IP
Example:
10.60.20.10 → AD Server
All three can be used together.
14. Enterprise Segmentation Example
INTERNET
│
FIREWALL
│
CORE ROUTER
│
┌──────────────────┼──────────────────┐
│ │ │
VLAN 10 VLAN 20 VLAN 30
Corporate Servers Security
10.60.10.0/24 10.60.20.0/27 10.60.30.0/27
│ │ │
Laptops AD/DNS Kali
Desktops Fileserver Burp
Printers Applications Security VMs
│ │ │
└──────────── Firewall ACLs ──────────┘
│
VLAN 40
CTF / LAB
10.60.40.0/26
│
Vulnerable VMs
Example security policy:
Corporate → Internet ALLOW
Corporate → Servers LIMITED
Corporate → CTF DENY
Security → CTF ALLOW
Security → Servers LIMITED
Security → Internet ALLOW
CTF → Corporate DENY
CTF → Servers DENY
15. Private IPv4 Address Ranges
RFC 1918 private address space:
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
Examples:
10.60.20.0/24
172.20.50.0/24
192.168.150.0/24
These ranges are intended for private/internal networks.
16. Networking Commands
Windows
ipconfig
ipconfig /all
ipconfig /release
ipconfig /renew
ping 192.168.150.2
tracert 8.8.8.8
route print
nslookup google.com
Linux
ip a
ip route
ip neigh
ping -c 4 192.168.150.2
ping -c 4 8.8.8.8
traceroute 8.8.8.8
ss -tulpn
resolvectl status
17. Basic Network Troubleshooting
Check in this order:
1. NIC connected?
↓
2. Correct VMware network?
↓
3. Correct IP address?
↓
4. Correct subnet mask?
↓
5. Correct default gateway?
↓
6. DNS working?
↓
7. Firewall / ACL?
↓
8. Destination reachable?
18. Quick Reference
STATIC IP
Manual, fixed address
DHCP
Automatic address assignment
DHCP POOL
Range of addresses DHCP can distribute
SUBNET
A logical IP network
SUBNETTING
Dividing a larger network into smaller networks
VLAN
Logical Layer-2 network segmentation
DEFAULT GATEWAY
Router used to reach another network
NAT
Translates private VM traffic through another network/interface
CIDR
Notation such as /24, /26, /27
BROADCAST
Special address used to communicate with all hosts in a subnet
Core concept
Subnetting
↓
Creates separate networks
VLANs
↓
Separates Layer-2 traffic
DHCP
↓
Automatically assigns addresses
Static IP
↓
Keeps a device at a manually assigned address
Routing
↓
Connects different networks
Firewall / ACL
↓
Controls communication between networks