Native SFTP Support in Windows Server 2012 R2: IIS Configuration and Alternatives


1 views

Windows Server 2012 R2 does not include native SFTP support through IIS. The built-in FTP Server role only provides traditional FTP and FTPS (FTP over SSL/TLS) functionality. This is a common point of confusion for administrators transitioning from Unix-like systems where SFTP is typically bundled with SSH.

The FTP service in IIS was designed before SFTP became the industry standard for secure file transfers. Microsoft's implementation:

  • Uses separate control and data channels (unlike SFTP's single encrypted channel)
  • Requires explicit SSL configuration for FTPS
  • Lacks SSH protocol integration which SFTP requires

Option 1: Third-Party SFTP Servers

Popular choices include:

# FreeSSHD installation example (command line)
msiexec /i FreeSSHd.msi /quiet /norestart

Option 2: Using OpenSSH (Windows 10+/Server 2019+)

For newer Windows versions:

# PowerShell to install OpenSSH server
Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
Start-Service sshd
Set-Service -Name sshd -StartupType 'Automatic'

While not SFTP, FTPS can be a viable alternative:

// Web.config snippet for requiring SSL
<system.ftpServer>
  <ssl controlChannelPolicy="SslRequire" dataChannelPolicy="SslRequire">
</system.ftpServer>

When implementing any solution:

  • Always use certificate-based authentication
  • Implement IP restrictions where possible
  • Regularly audit transfer logs
  • Consider implementing MFA for administrative access

SFTP implementations on Windows typically show:

  • 20-30% lower throughput compared to native Linux implementations
  • Higher memory usage due to Windows' process model
  • Additional CPU overhead from cryptographic operations

Windows Server 2012 R2 includes an FTP Server role through IIS (Internet Information Services), but it's crucial to note that this only provides traditional FTP/FTPS functionality, not SFTP. The confusion often arises because:

# PowerShell command to check installed Windows features
Get-WindowsFeature -Name Web-Ftp-Server

While both protocols serve file transfer purposes, they differ fundamentally:

  • SFTP (SSH File Transfer Protocol) operates over SSH (port 22)
  • FTPS (FTP Secure) is FTP with SSL/TLS (ports 21/990)
  • SFTP provides better security through SSH encryption

Microsoft doesn't provide native SFTP support in this version, but you have several options:

Option 1: Using OpenSSH (Modern Approach)

Windows 10/Server 2019+ includes OpenSSH, but for 2012 R2 you can install it manually:

# Download and install OpenSSH for Windows
# From PowerShell (admin):
iex ((New-Object System.Net.WebClient).DownloadString('https://raw.githubusercontent.com/PowerShell/Win32-OpenSSH/master/Install-OpenSSH.ps1'))

Option 2: Third-party SFTP Servers

Popular alternatives include:

  • Bitvise SFTP Server
  • freeSSHd
  • SolarWinds SFTP/SCP Server

Option 3: IIS with SFTP Bridge

You can configure IIS to work with an SFTP bridge service:

# Example setup using IIS FTPS with SFTP gateway
# 1. Configure IIS FTPS with SSL certificate
# 2. Set up SFTP gateway service forwarding to local FTPS

When implementing SFTP on legacy Windows servers:

  • Always use strong SSH key authentication
  • Disable deprecated SSH protocols (SSHv1)
  • Regularly update third-party SFTP components

For production environments, consider upgrading to Windows Server 2019/2022 where OpenSSH is included natively:

# On Windows Server 2019+
Add-WindowsFeature -Name OpenSSH.Server
Start-Service sshd
Set-Service -Name sshd -StartupType Automatic