DHCP Integration

This guide covers integrating FOG Docker with existing DHCP servers for PXE boot configuration.

Overview

FOG Docker can work with any DHCP server by configuring the appropriate PXE boot options. This guide covers integration with:

ISC DHCP Server (Linux/Unix)
Windows DHCP Server
pfSense DHCP
MikroTik RouterOS
Ubiquiti UniFi

DHCP Configuration Requirements

Required DHCP Options

For PXE boot to work, your DHCP server must provide:

Option 66 (Next Server): IP address of your FOG server (use FOG_TFTP_HOST value)
Option 67 (Boot File): Name of the boot file for the client architecture (use FOG_DHCP_BOOTFILE_BIOS, FOG_DHCP_BOOTFILE_UEFI32, FOG_DHCP_BOOTFILE_UEFI64, or FOG_DHCP_BOOTFILE_ARM64)

Boot File Names

Client Type	Boot File	Environment Variable	Description
Legacy BIOS (Arch:00000)	`undionly.kkpxe`	`FOG_DHCP_BOOTFILE_BIOS`	Traditional BIOS PXE boot
UEFI 32-bit (Arch:00002, 00006)	`i386-efi/snponly.efi`	`FOG_DHCP_BOOTFILE_UEFI32`	UEFI 32-bit clients
UEFI 64-bit (Arch:00007, 00008, 00009)	`snponly.efi`	`FOG_DHCP_BOOTFILE_UEFI64`	UEFI 64-bit clients (x86_64)
UEFI ARM64 (Arch:00011)	`arm64-efi/snponly.efi`	`FOG_DHCP_BOOTFILE_ARM64`	ARM64 UEFI clients
SURFACE-PRO-4	`snponly.efi`	`FOG_DHCP_BOOTFILE_UEFI64`	Microsoft Surface Pro 4
Apple-Intel-Netboot	`snponly.efi`	`FOG_DHCP_BOOTFILE_UEFI64`	Apple Intel Macs

ISC DHCP Server (Linux/Unix)

Basic Configuration

Edit /etc/dhcp/dhcpd.conf:

# Global settings
option domain-name "your-domain.com";
option domain-name-servers 8.8.8.8, 8.8.4.4;
default-lease-time 600;
max-lease-time 7200;

# Subnet configuration
subnet 192.168.1.0 netmask 255.255.255.0 {
    range 192.168.1.100 192.168.1.200;
    option routers 192.168.1.1;
    option broadcast-address 192.168.1.255;
    
    # FOG PXE Boot Configuration
    next-server 192.168.1.100;  # Your FOG server IP
    
    # BIOS clients (Arch:00000)
    if substring(option vendor-class-identifier, 0, 9) = "PXEClient" {
        if substring(option vendor-class-identifier, 15, 5) = "00000" {
            filename "undionly.kkpxe";
        }
    }
    
    # UEFI 64-bit clients (Arch:00007)
    if substring(option vendor-class-identifier, 0, 9) = "PXEClient" {
        if substring(option vendor-class-identifier, 15, 5) = "00007" {
            filename "snponly.efi";
        }
    }
}

Advanced Configuration with Architecture Detection

# Global settings
option domain-name "your-domain.com";
option domain-name-servers 8.8.8.8, 8.8.4.4;
default-lease-time 600;
max-lease-time 7200;

# Subnet configuration
subnet 192.168.1.0 netmask 255.255.255.0 {
    range 192.168.1.100 192.168.1.200;
    option routers 192.168.1.1;
    option broadcast-address 192.168.1.255;
    
    # FOG PXE Boot Configuration
    next-server 192.168.1.100;  # Your FOG server IP
    
    # Architecture detection and boot file selection
    if substring(option vendor-class-identifier, 0, 9) = "PXEClient" {
        # BIOS clients (Arch:00000)
        if substring(option vendor-class-identifier, 15, 5) = "00000" {
            filename "undionly.kkpxe";
        }
        # UEFI 32-bit clients (Arch:00002, 00006)
        elsif substring(option vendor-class-identifier, 15, 5) = "00002" {
            filename "i386-efi/snponly.efi";
        }
        elsif substring(option vendor-class-identifier, 15, 5) = "00006" {
            filename "i386-efi/snponly.efi";
        }
        # UEFI 64-bit clients (Arch:00007, 00008, 00009)
        elsif substring(option vendor-class-identifier, 15, 5) = "00007" {
            filename "snponly.efi";
        }
        elsif substring(option vendor-class-identifier, 15, 5) = "00008" {
            filename "snponly.efi";
        }
        elsif substring(option vendor-class-identifier, 15, 5) = "00009" {
            filename "snponly.efi";
        }
        # UEFI ARM64 clients (Arch:00011)
        elsif substring(option vendor-class-identifier, 15, 5) = "00011" {
            filename "arm64-efi/snponly.efi";
        }
        # Default fallback
        else {
            filename "undionly.kkpxe";
        }
    }
}

Restart DHCP Service

# Restart DHCP server
sudo systemctl restart isc-dhcp-server

# Check status
sudo systemctl status isc-dhcp-server

# Check configuration
sudo dhcpd -t

Windows DHCP Server

Using DHCP Management Console

Open DHCP Management Console
Right-click on your server → Properties
Go to Advanced tab
Click “Vendor Classes” → Add
Create vendor classes for different architectures

Using PowerShell

# Set DHCP server options
Set-DhcpServerv4OptionValue -ComputerName "your-dhcp-server" -OptionId 66 -Value "192.168.1.100"
Set-DhcpServerv4OptionValue -ComputerName "your-dhcp-server" -OptionId 67 -Value "undionly.kkpxe"

# For UEFI 64-bit clients, create a policy
Add-DhcpServerv4Policy -Name "UEFI-Clients" -Condition OR -MacAddress "00-15-5D-*"
Set-DhcpServerv4Policy -Name "UEFI-Clients" -OptionId 67 -Value "snponly.efi"

Using netsh (Command Line)

# Set global options
netsh dhcp server scope 192.168.1.0 set optionvalue 66 IPADDRESS 192.168.1.100
netsh dhcp server scope 192.168.1.0 set optionvalue 67 STRING "undionly.kkpxe"

# For UEFI 64-bit clients, create a reservation or policy
netsh dhcp server scope 192.168.1.0 add reservedip 192.168.1.150 00-15-5D-01-02-03 "UEFI-Client"
netsh dhcp server reservedip 192.168.1.150 set optionvalue 67 STRING "snponly.efi"

pfSense DHCP

Web Interface Configuration

Go to Services → DHCP Server
Edit your DHCP scope
Scroll down to “Additional BOOTP/DHCP Options”
Add the following options:

Number	Type	Value	Description
66	Text	`192.168.1.100`	Next Server (FOG server IP)
67	Text	`undionly.kkpxe`	Boot File Name (BIOS) or `snponly.efi` (UEFI 64-bit)

Advanced Configuration

For different architectures, create multiple DHCP scopes or use custom options:

# In pfSense shell or config
# Option 66: Next Server
option 66 "192.168.1.100";

# Option 67: Boot File (BIOS)
option 67 "undionly.kkpxe";

# For UEFI clients, you may need to create separate scopes
# or use MAC address reservations

MikroTik RouterOS

Using WinBox/WebFig

Go to IP → DHCP Server
Edit your DHCP network
Go to “Options” tab
Add the following options:

Name	Code	Value
next-server	66	`192.168.1.100`
boot-file-name	67	`undionly.kkpxe` (BIOS) or `snponly.efi` (UEFI 64-bit)

Using Command Line

# Set DHCP options
/ip dhcp-server option add name="next-server" code=66 value=0xC0A80164
/ip dhcp-server option add name="boot-file-name" code=67 value="undionly.kkpxe"

# Apply to DHCP network
/ip dhcp-server network set [find address="192.168.1.0/24"] next-server=192.168.1.100 boot-file-name=undionly.kkpxe

Ubiquiti UniFi

Using UniFi Controller

Go to Settings → Networks
Edit your network
Go to “Advanced” section
Enable “DHCP Options”
Add the following options:

Number	Type	Value
66	String	`192.168.1.100`
67	String	`undionly.kkpxe` (BIOS) or `snponly.efi` (UEFI 64-bit)

Using JSON Configuration

{
  "dhcpOptions": [
    {
      "number": 66,
      "type": "string",
      "value": "192.168.1.100"
    },
    {
      "number": 67,
      "type": "string", 
      "value": "undionly.kkpxe"
    }
  ]
}

HTTPBoot Configuration

For UEFI clients that support HTTPBoot, you can configure HTTP URLs instead of TFTP files:

ISC DHCP Server

# HTTPBoot configuration for UEFI clients
if substring(option vendor-class-identifier, 0, 9) = "PXEClient" {
    if substring(option vendor-class-identifier, 15, 5) = "00007" {
        # HTTPBoot URL for UEFI clients
        option vendor-class-identifier "HTTPClient:Arch:00007:UNDI:003016";
        filename "http://192.168.1.100/fog/service/ipxe/snponly.efi";
    }
}

Windows DHCP Server

# Set HTTPBoot option for UEFI clients
Set-DhcpServerv4OptionValue -ComputerName "your-dhcp-server" -OptionId 67 -Value "http://192.168.1.100/fog/service/ipxe/snponly.efi"

Testing DHCP Configuration

Test DHCP Options

# Test DHCP options from client
dhclient -v eth0

# Check received options
cat /var/lib/dhcp/dhclient.leases

# Test PXE boot
# Boot a client machine and check if it receives correct options

Verify PXE Boot

Boot a client machine via PXE
Check if it receives the correct next-server and boot file
Verify the client can download the boot file from FOG server
Check FOG logs for client connections

Troubleshooting

Common Issues

Client Not Getting PXE Options

Symptoms: Client boots but doesn’t get PXE options Solutions:

Check DHCP server configuration
Verify DHCP server is running
Check network connectivity
Verify client is in correct subnet

Wrong Boot File for Architecture

Symptoms: Client gets wrong boot file for its architecture Solutions:

Check vendor class identifier detection
Verify architecture-specific options
Test with different client types

TFTP Timeout Errors

Symptoms: Client can’t download boot file Solutions:

Check TFTP server is running on FOG server
Verify firewall rules allow TFTP (port 69/UDP)
Check file permissions on boot files
Test TFTP connectivity manually

Debug Commands

# Check DHCP server status
systemctl status isc-dhcp-server

# Check DHCP leases
cat /var/lib/dhcp/dhcpd.leases

# Test DHCP options
dhclient -v eth0

# Check TFTP server
systemctl status tftpd-hpa

# Test TFTP connectivity
tftp 192.168.1.100
tftp> get undionly.kkpxe
tftp> quit

Best Practices

Security

Use DHCP reservations for known clients
Implement DHCP snooping on switches
Monitor DHCP traffic for anomalies
Use secure boot when possible

Performance

Optimize DHCP lease times for your environment
Use DHCP pools efficiently
Monitor DHCP server performance
Implement DHCP failover for redundancy

Maintenance

Regular backup of DHCP configuration
Monitor DHCP logs for issues
Update boot files when FOG is updated
Test PXE boot after any changes

Next Steps

After configuring DHCP integration:

Network Boot Setup - Verify PXE and HTTPBoot configuration
Configuration Guide - Optimize FOG configuration
Troubleshooting Guide - Address any issues