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introduction

The “HTTP 413 (Request Entity Too Large)” error occurs when a client tries to send a request that exceeds the server’s configured size limit. This is especially common with large file uploads or wide data requests. In this blog, we will look at the causes of this error in IIS, how to resolve it, and how to adjust the configuration for WCF services in particular.

What is an HTTP 413 error?

The HTTP 413 status code “Request Entity Too Large” indicates that the server cannot process the request because the payload size exceeds the server’s allowable limits. This error usually occurs when sending large files or large amounts of data in a request.

Why am I getting an HTTP 413 error in IIS? IIS has some built-in limits to prevent the server from being overwhelmed by too many requests. Common causes include:

• Request Filtering Restrictions: Configured via maxAllowedContentLength in web.config or ApplicationHost.config.
• Upload buffering: Controlled by the uploadReadAheadSize property.
• ASP.NET Settings: Governed by maxRequestLength in web.config.
• WCF Service: Both the service and client configurations need to be tuned to handle large messages.

How to fix HTTP 413 error in IIS

1. Adjust maxAllowedContentLength in web.config

Increase the maximum request size allowed by IIS.

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2. Modify uploadReadAheadSize

Configure IIS to handle larger request sizes.

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3. Updating maxRequestLength in ASP.NET

For ASP.NET applications, increase maxRequestLength.

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4. Configuring WCF services (If WCF throws 413 exception)

When dealing with WCF services, especially when both the service and the client are hosted on IIS, you need to configure several properties to handle large messages efficiently.

Service Configuration:

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Client Configuration:

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http://YourServiceURL” binding=”basicHttpBinding” binding configuration=”LargeRequestClientBinding” contract=”IYourService” />

explanation:

• maxBufferSize and maxBufferPoolSize control the size of the buffer used to process messages.
• maxReceivedMessageSize sets the maximum size of a message that can be received.
• The readerQuotas setting controls the maximum size of various aspects of a message to prevent attacks and ensure server stability.

Additional Considerations

If adjusting these configurations doesn’t fix the issue, get a memory dump of the exception along with a WCF trace. That will help point out some issues. Check your configuration thoroughly to make sure it has the correct service name. If you are only working with ASP.NET web applications and want to upload files larger than 2GB, you should consider leveraging WebDav.

conclusion

“HTTP 413 (Request Entity Too Large)” errors can be managed by configuring IIS and WCF settings to handle larger requests more efficiently. Understanding and adjusting these settings will allow your server to handle large file uploads and wide data requests without issue.