While Linux systems use sysctl net.ipv4.ip_forward=1 to enable IP packet forwarding, Windows implements this functionality differently through registry settings and network configuration. The Windows equivalent allows a server to act as a router between network interfaces.

For Windows Server 2008 R2, follow these steps to enable IP forwarding:

REG ADD HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters /v IPEnableRouter /t REG_DWORD /d 1 /f

Or through PowerShell:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -Name "IPEnableRouter" -Value 1

After making the registry change, verify the setting with:

reg query HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters /v IPEnableRouter

You should see output similar to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    IPEnableRouter    REG_DWORD    0x1

Windows Firewall may block forwarded packets. Ensure proper rules are configured:

netsh advfirewall firewall add rule name="IP Forwarding" dir=in action=allow

Unlike Linux's sysctl which requires persistence through /etc/sysctl.conf, the Windows registry change is permanent and survives reboots automatically.

• Restart the server after making changes
• Check routing tables with route print
• Verify interfaces with ipconfig /all
• Test connectivity between networks

While Linux systems use sysctl net.ipv4.ip_forward=1 to enable IP packet forwarding, Windows handles this functionality differently through registry settings and network interface configurations. Windows Server 2008 R2 provides multiple ways to achieve this network routing capability.

The most direct method to enable IP forwarding is through the Windows Registry:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
"IPEnableRouter"=dword:00000001

After making this change, reboot your server for the settings to take effect.

For administrators preferring command-line tools, PowerShell provides a way to modify this setting:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" 
-Name "IPEnableRouter" -Value 1
Restart-Computer -Force

You can also configure routing using Windows' built-in network shell utility:

netsh routing ip nat install
netsh routing ip nat set global state=enable

To confirm that IP forwarding is active, use this PowerShell command:

Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" 
-Name "IPEnableRouter" | Select-Object IPEnableRouter

Remember that enabling IP forwarding makes your server act as a router. Ensure proper firewall rules are configured:

netsh advfirewall firewall add rule name="Allow Routing" dir=in action=allow protocol=any