Quick Setup Guide

1. File Location

Place favicons in wwwroot or site root folder

2. MIME Types

Configure in IIS Manager or web.config

3. Caching

Set cache headers for optimal performance

Basic IIS Favicon Setup

Step-by-Step Configuration

Step 1: File Placement

Place your favicon files in the appropriate directory:

C:\inetpub\wwwroot\YourSite\
  favicon.ico
    favicon-16x16.png
    favicon-32x32.png
    favicon-96x96.png
    favicon-512x512.png
    apple-touch-icon.png
  android-chrome-192x192.png
  android-chrome-512x512.png
  site.webmanifest

Step 2: Verify Permissions

Ensure IIS application pool identity has read access:

Right-click favicon.ico ? Properties ? Security
Add IIS AppPool\YourAppPoolName with Read permissions
Or use IUSR account for simpler setup

Quick Test: Access http://yoursite.com/favicon.ico directly in browser to verify file is served correctly.

MIME Type Configuration

Configure Static Content Types

Method 1: IIS Manager (GUI)

Open IIS Manager
Select your website
Double-click "MIME Types"
Click "Add..." in right panel
Add missing MIME types from table below

Extension	MIME Type	Required
`.ico`	`image/x-icon`	Yes
`.png`	`image/png`	Yes
`.svg`	`image/svg+xml`	Recommended
`.webmanifest`	`application/manifest+json`	PWA

Method 2: web.config (Recommended)

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.webServer>
    <staticContent>
      <!-- ICO files -->
      <remove fileExtension=".ico" />
      <mimeMap fileExtension=".ico" mimeType="image/x-icon" />
      
      <!-- PNG files (usually pre-configured) -->
      <remove fileExtension=".png" />
      <mimeMap fileExtension=".png" mimeType="image/png" />
      
      <!-- SVG files -->
      <remove fileExtension=".svg" />
      <mimeMap fileExtension=".svg" mimeType="image/svg+xml" />
      
      <!-- Web App Manifest -->
      <remove fileExtension=".webmanifest" />
      <mimeMap fileExtension=".webmanifest" mimeType="application/manifest+json" />
    </staticContent>
  </system.webServer>
</configuration>

Note: <remove> prevents duplicate MIME type errors if entry already exists.

Caching & Performance

Optimize Favicon Delivery

Complete web.config with Caching

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.webServer>
    
    <!-- MIME Types -->
    <staticContent>
      <remove fileExtension=".ico" />
      <mimeMap fileExtension=".ico" mimeType="image/x-icon" />
      <remove fileExtension=".svg" />
      <mimeMap fileExtension=".svg" mimeType="image/svg+xml" />
      <remove fileExtension=".webmanifest" />
      <mimeMap fileExtension=".webmanifest" mimeType="application/manifest+json" />
      
      <!-- Enable client caching for 1 year -->
      <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="365.00:00:00" />
    </staticContent>
    
    <!-- Custom Headers for Favicon -->
    <httpProtocol>
      <customHeaders>
        <add name="Cache-Control" value="public, max-age=31536000, immutable" />
      </customHeaders>
    </httpProtocol>
    
    <!-- Enable Static Compression -->
    <urlCompression doStaticCompression="true" doDynamicCompression="false" />
    
  </system.webServer>
</configuration>

Location-Specific Caching (Advanced)

Apply different cache rules for favicons only:

<configuration>
  <!-- Favicon-specific caching -->
  <location path="favicon.ico">
    <system.webServer>
      <staticContent>
        <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="365.00:00:00" />
      </staticContent>
      <httpProtocol>
        <customHeaders>
          <add name="Cache-Control" value="public, max-age=31536000" />
        </customHeaders>
      </httpProtocol>
    </system.webServer>
  </location>
  
  <!-- All PNG favicons -->
  <location path="favicon-16x16.png">
    <system.webServer>
      <staticContent>
        <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="365.00:00:00" />
      </staticContent>
    </system.webServer>
  </location>
</configuration>

GZIP Compression

Enable Static Compression

IIS Manager Configuration

Open IIS Manager
Select your server or website
Double-click "Compression"
Check "Enable static content compression"
Click "Apply"

web.config Compression Settings

<system.webServer>
  <urlCompression 
    doStaticCompression="true" 
    doDynamicCompression="false" 
    dynamicCompressionBeforeCache="false" />
  
  <!-- Add ICO and SVG to compression types (applicationHost.config) -->
  <httpCompression>
    <staticTypes>
      <add mimeType="image/svg+xml" enabled="true" />
      <add mimeType="image/x-icon" enabled="true" />
    </staticTypes>
  </httpCompression>
</system.webServer>

Note: ICO compression may not significantly reduce file size. SVG files benefit greatly from GZIP compression.

URL Rewrite for Favicon

Redirect Missing Favicon Requests

Install URL Rewrite Module

Download from: Microsoft IIS URL Rewrite

web.config Rewrite Rules

<system.webServer>
  <rewrite>
    <rules>
      <!-- Redirect old favicon.ico to new location -->
      <rule name="Redirect Favicon" stopProcessing="true">
        <match url="^old-favicon\.ico$" />
        <action type="Redirect" url="/favicon.ico" redirectType="Permanent" />
      </rule>
      
      <!-- Serve default favicon for missing requests -->
      <rule name="Serve Default Favicon" stopProcessing="true">
        <match url="^(.*/)?favicon\.ico$" />
        <conditions>
          <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
        </conditions>
        <action type="Rewrite" url="/favicon.ico" />
      </rule>
    </rules>
  </rewrite>
</system.webServer>

ASP.NET Core on IIS

.NET Applications Favicon Setup

File Location

Place favicons in wwwroot folder:

YourProject/
  wwwroot/
    favicon.ico
    favicon-16x16.png
    favicon-32x32.png
    apple-touch-icon.png

Program.cs Configuration (ASP.NET Core 6+)

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

// Enable static files (includes favicons)
app.UseStaticFiles(new StaticFileOptions
{
    OnPrepareResponse = ctx =>
    {
        // Set caching for favicon files
        if (ctx.File.Name.Contains("favicon") || 
            ctx.File.Name.Contains("apple-touch-icon"))
        {
            ctx.Context.Response.Headers.Append(
                "Cache-Control", "public,max-age=31536000");
        }
    }
});

app.Run();

web.config for ASP.NET Core

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.webServer>
    <handlers>
      <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
    </handlers>
    <aspNetCore processPath="dotnet" arguments=".\YourApp.dll" stdoutLogEnabled="false" />
    
    <!-- Static files handled by ASP.NET Core middleware -->
    <staticContent>
      <remove fileExtension=".ico" />
      <mimeMap fileExtension=".ico" mimeType="image/x-icon" />
    </staticContent>
  </system.webServer>
</configuration>

Troubleshooting IIS Favicon Issues

Solutions:

Verify file exists in physical path (C:\inetpub\wwwroot\...)
Check IIS application pool identity has Read permissions
Ensure MIME type is configured for .ico extension
Check URL Rewrite rules aren't blocking request
Test direct URL: http://site.com/favicon.ico

Fixes:

Clear browser cache (Ctrl+Shift+R)
Add version query string: favicon.ico?v=2
Restart IIS application pool
Run iisreset in admin cmd
Check if Output Caching is enabled and reset it
Verify web.config cache headers

Error: Cannot add duplicate collection entry of type 'mimeMap'
Solution:

Add <remove fileExtension=".ico" /> before <mimeMap>
Or configure at server level, not site level
Check parent applicationHost.config for existing entries

Cause: Missing static file handler or incorrect MIME type
Solution:

Ensure Static Content role is installed in IIS
Verify StaticFileModule is enabled
Check handler mappings for static files
Add correct MIME type in web.config

IIS Favicon Best Practices

? Recommendations

Use web.config for MIME types (portable across servers)
Set long cache expiration (1 year minimum)
Enable static compression for SVG files
Place favicons in wwwroot or site root
Set proper file permissions (Read for IIS user)
Use URL Rewrite for legacy paths
Monitor IIS logs for 404 favicon errors
Test with IIS Express locally first

? Common Mistakes

Not configuring MIME types (404 errors)
Forgetting file permissions for app pool identity
Placing favicons outside physical path
Not setting cache headers (poor performance)
Using dynamic compression for static files
Blocking favicon in URL Rewrite rules
Not testing after IIS updates
Hardcoding server-specific paths

Useful PowerShell Commands

IIS Management Commands

Common IIS Commands

# Reset IIS
iisreset

# Restart specific application pool
Restart-WebAppPool -Name "YourAppPoolName"

# Check if MIME type exists
Get-WebConfigurationProperty -Filter "//staticContent/mimeMap" `
  -PSPath "IIS:\Sites\Default Web Site" -Name *

# Add MIME type via PowerShell
Add-WebConfigurationProperty -Filter "//staticContent" `
  -PSPath "IIS:\Sites\Default Web Site" `
  -Name "." -Value @{fileExtension='.webmanifest'; mimeType='application/manifest+json'}

# Enable static compression
Set-WebConfigurationProperty -Filter "/system.webServer/urlCompression" `
  -PSPath "IIS:\Sites\Default Web Site" `
  -Name "doStaticCompression" -Value $true

# List all websites
Get-Website

# Get site physical path
(Get-Website -Name "Default Web Site").PhysicalPath

Test Favicon Availability

# Test if favicon exists
Test-Path "C:\inetpub\wwwroot\favicon.ico"

# Get favicon file info
Get-ChildItem "C:\inetpub\wwwroot\favicon.ico" | Select-Object Name, Length, LastWriteTime

# Test HTTP response
Invoke-WebRequest -Uri "http://localhost/favicon.ico" -Method Head

# Check MIME type in response
(Invoke-WebRequest -Uri "http://localhost/favicon.ico").Headers["Content-Type"]