ASP.NET Framework 4.x Web.config Configuration Guide Print

Essential web.config Settings for ASP.NET 4.x

Configure your ASP.NET Framework 4.x application properly for Plesk Windows hosting.

Basic web.config Structure

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <appSettings>
    <add key="Setting1" value="Value1" />
  </appSettings>

  <connectionStrings>
    <add name="DefaultConnection"
         connectionString="Server=localhost;Database=myDb;User Id=user;Password=pass;"
         providerName="System.Data.SqlClient" />
  </connectionStrings>

  <system.web>
    <compilation debug="false" targetFramework="4.8" />
    <httpRuntime targetFramework="4.8" maxRequestLength="32768" />
    <customErrors mode="RemoteOnly" defaultRedirect="~/Error" />
  </system.web>
</configuration>

Custom Error Pages

<system.web>
  <customErrors mode="RemoteOnly">
    <error statusCode="404" redirect="~/Errors/NotFound" />
    <error statusCode="500" redirect="~/Errors/ServerError" />
  </customErrors>
</system.web>

<system.webServer>
  <httpErrors errorMode="Custom">
    <remove statusCode="404" />
    <error statusCode="404" path="/Errors/NotFound" responseMode="ExecuteURL" />
  </httpErrors>
</system.webServer>

Authentication Settings

<system.web>
  <authentication mode="Forms">
    <forms loginUrl="~/Account/Login" timeout="30" slidingExpiration="true" />
  </authentication>
  <authorization>
    <deny users="?" />  <!-- Deny anonymous -->
  </authorization>
</system.web>

Session State

<system.web>
  <sessionState mode="InProc" timeout="20" />
</system.web>

Machine Key (Required for Web Farms/Load Balancing)

<system.web>
  <machineKey
    validationKey="YOUR_VALIDATION_KEY"
    decryptionKey="YOUR_DECRYPTION_KEY"
    validation="SHA1"
    decryption="AES" />
</system.web>

Tip: Generate keys using IIS Manager or online tools.

URL Rewrite (HTTPS Redirect)

<system.webServer>
  <rewrite>
    <rules>
      <rule name="HTTPS Redirect" stopProcessing="true">
        <match url="(.*)" />
        <conditions>
          <add input="{HTTPS}" pattern="off" ignoreCase="true" />
        </conditions>
        <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" redirectType="Permanent" />
      </rule>
    </rules>
  </rewrite>
</system.webServer>

SMTP Email Settings

<system.net>
  <mailSettings>
    <smtp from="noreply@yourdomain.com">
      <network host="mail.yourdomain.com"
               port="587"
               userName="user@yourdomain.com"
               password="yourpassword"
               enableSsl="true" />
    </smtp>
  </mailSettings>
</system.net>

Increase Upload Limits

<system.web>
  <httpRuntime maxRequestLength="51200" /> <!-- 50MB in KB -->
</system.web>

<system.webServer>
  <security>
    <requestFiltering>
      <requestLimits maxAllowedContentLength="52428800" /> <!-- 50MB in bytes -->
    </requestFiltering>
  </security>
</system.webServer>

Common Issues

• Yellow Screen of Death: Set customErrors mode="On" for production
• ViewState errors: Add machineKey for consistent encryption
• Upload fails: Increase maxRequestLength and maxAllowedContentLength
• Session lost: Check sessionState timeout and Application Pool recycling