Requests Fail When the Input Exceeds the Maximum Length

Requests containing lengthy input may fail when the input exceeds the maximum length supported by the server. The input can consist of any text or characters, such as a search query containing a long list of values or a value entered in a field, such as a custom attribute.

The same request typically succeeds when the input is shortened, indicating that the issue is related to the request length rather than the input content itself.

SOTI MobiControl

The input is included as part of the HTTP request. If the request exceeds the server's configured size limits (such as MaxRequestBytes and MaxFieldLength) or the maximum allowed URL length, the server rejects the request.

The actual request size can be significantly larger than the number of characters entered due to the following factors:

• Character encoding: Special characters are encoded before being sent. For example, # is converted to %23.
• Multiple encoding passes: Some values may be encoded more than once as the request is processed. For example, # becomes %23 after the first encoding, %2523 after the second, and %252523 after the third. As a result, a single character can occupy up to seven characters in the request.
• Additional request data: Cookies and other HTTP headers also contribute to the overall request size and count toward the applicable limits.

This behavior applies to special characters in general, not just non-English or Unicode characters.

Important: The following settings apply to all applications on the server that use HTTP.sys, including SOTI MobiControl. Before making any changes, back up the Windows registry and test the changes in a non-production environment.

Follow these steps to increase the server request size limits:

1. Open Command Prompt as an administrator.
2. Run the following command to set MaxRequestBytes to 65534:

   reg add HKLM\SYSTEM\CurrentControlSet\Services\HTTP\Parameters /v MaxRequestBytes /t REG_DWORD /d 65534 /f
   

3. Run the following command to set MaxFieldLength to 65534:

   reg add HKLM\SYSTEM\CurrentControlSet\Services\HTTP\Parameters /v MaxFieldLength /t REG_DWORD /d 65534 /f
   

4. Restart the server for the new registry values to take effect.
5. Submit the same request again to verify that it succeeds.

After applying these changes, requests can accommodate approximately twice as much input as before. The exact increase depends on the characters used, as special characters require additional space after encoding.

Status

The request size limits can be increased by applying the registry changes described above.

If the request continues to fail after these changes, the maximum URL length may have been reached. Increasing the request size limits does not necessarily resolve URL length restrictions.

If requests continue to fail after increasing the server request limits, contact SOTI Support for further assistance.