Tomcat: Request Entity Too Large (IIS, ISAPI)

This requires editing server.xml on your server in the server configuration (Server/conf) directory.

Issue:

One or more users see an error page displaying when connecting to iDashboards similar to:

The page was not displayed because the request entity is too large.

Commonly seen in Chrome, however Edge and Firefox are rarely affected by this issue. The Tomcat AJP1.3 connector has a max packet size of 8K by default. If (certain elements of) a request exceed this then the error can occur. This issue often arises when a user is a member multiple Active Directory groups which causes the header to be larger than the default settings allow. The iDashboards Support team has also seen this issue when using Asset Bank's WIASSOPlugin. This plugin connects to the Asset Bank website via Microsoft IIS and is configured to use Integrated Windows Authentication. When Asset Bank (or IIS) issues a challenge, a user's browser will include an authentication header in its next request. If Kerberos is used (default) then this header can be large, especially if the user is a member of many Organizational Units (OUs in Active Directory) as this information is included in the header.

Resolution:

This requires editing server.xml on your server in the server configuration (Server/conf) directory.

Caution: Changing the max packet size could cause issues with performance. We recommend cleaning out AD groups that are no longer necessary for the user and increase the max packet size as follows:

• Open /tomcat/conf/server.xml or iDashboards_SRV\Server\conf\server.xml and find the AJP 1.3 connector element.

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" tomcatAuthentication="false" URIEncoding="UTF-8"/>

• Add an attribute called packetSize with a value larger than 8192 (default).

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" tomcatAuthentication="false" URIEncoding="UTF-8" packetSize="16384"/>

• Open the /Tomcat/conf/worker.properties or iDashboards_SRV\Server\conf\worker.properties file used by isapi_redirect.dll filter
• Add the following at the end of the file:

worker.ajp13.max_packet_size=16384

• 16384 is the max packet size in bytes. This should be the same as the packetSize you set for the connector.

Technical Note: worker.ajp13.max_packet_size in worker.properties may not be necessary if the default buffer size in the isapi_redirect filter was changed to 64K at some point. This setting can then be ignored. Older versions of the filter may also have the buffer hard-coded to 8K where it would be necessary to update isapi_redirect.dll.

Disclaimer: iDashboards Technical Support Engineers are not Server or Active Directory Administrators who know in depth knowledge of them and their quirks. We often learn these skills on the job and have limited knowledge. We do our best to help you with your software in determining if: you are not leveraging the software in the best way for your data or you found a bug in the software, because we want to assist you in your success.

If the above is unable to resolve the issue, then please contact iDashboards Support for further assistance.