When working with Windows Server DHCP configuration, the option to specify multiple default gateways often raises questions about its practical applications. Unlike Linux's ISC DHCP where this is less common, Windows Server explicitly supports this configuration in its scope options.

Here are scenarios where distributing multiple default gateways makes technical sense:

• High Availability Networks: When implementing redundant routing infrastructure where secondary gateways serve as failover points
• Multi-homed Networks: In environments with multiple network egress points for different traffic types
• Gradual Migration: During network infrastructure upgrades where old and new gateways coexist

The Windows DHCP server handles multiple gateways by setting their priority through the Router Metric Base value. Here's how the DHCP option is structured:

Option 3: Router (Default Gateway)
   Value: 192.168.1.1, 192.168.1.254
   Metric: 10, 20

Different operating systems handle multiple gateways differently:

For administrators preferring automation, here's how to configure multiple gateways via PowerShell:

Add-DhcpServerv4OptionValue -ScopeId 192.168.1.0 
    -Router 192.168.1.1,192.168.1.254 
    -Force

Common challenges include:

• Client compatibility: Some older devices may ignore secondary gateways
• Asymmetric routing: May occur if gateways don't have synchronized routing tables
• ARP cache issues: Clients might need manual ARP cache flushing during failover

Essential commands to verify gateway functionality:

# Check DHCP lease information
Get-DhcpServerv4Lease -ScopeId 192.168.1.0

# Verify client routing table
route print (Windows)
ip route show (Linux)

When configuring a Windows DHCP server, the ability to distribute multiple default gateways (option 003) presents interesting possibilities for network architecture. Unlike Linux's ISC DHCP where multiple gateways typically require custom scripts, Windows Server natively supports this functionality through its scope options.

Here are scenarios where distributing multiple gateways makes sense:

1. Redundant network paths for critical systems
2. Gradual migration between network segments
3. Load balancing across multiple routers
4. Testing failover scenarios without client reconfiguration

The PowerShell approach provides more control than the GUI wizard:

# Add primary gateway
Set-DhcpServerv4OptionValue -Router 192.168.1.1

# Add secondary gateway
Set-DhcpServerv4OptionValue -Router 192.168.1.2 -Append

Client handling varies significantly:

• Windows clients: Use first gateway until failure, then fail over
• Linux clients: Typically use all gateways with metric-based routing
• Network devices: Behavior depends on vendor implementation

For a weighted gateway distribution:

# Set primary gateway with lower metric
Set-DhcpServerv4OptionValue -Router "192.168.1.1,192.168.1.2" -Force

# Configure class-based options for different device types
Add-DhcpServerv4Class -Name "HighPriority" -Data "ManufacturerA"
Set-DhcpServerv4OptionValue -Router "192.168.1.3" -UserClass "HighPriority"

When debugging multiple gateway setups:

# Check assigned gateways on client
ipconfig /all | find "Default Gateway"  # Windows
ip route show default                  # Linux

# Verify DHCP server configuration
Get-DhcpServerv4OptionValue -OptionId 3 -ScopeId 10.0.0.0

Consider these when multiple gateways don't meet requirements:

1. VRRP/HSRP for transparent failover
2. Policy-based routing on network devices
3. ECMP (Equal-Cost Multi-Path) routing