passthrough.dll is a plugin that can be configured into a "front-end"
Sun Java System Web Server.
It can be used to forward requests to "back-end" web servers.

Are there any known issues with passthrough.dll which cause it to not
pass as many bytes of POST data as the Content-Length HTTP header says?

We have a back-end Sun Java System Web Server that complains
WEB3011: Read of HTTP Request POST Parameters failed: read < content
length
but only with certain POST data (quite a large form), and only if the
request goes through the front-end web server, rather than directly to
the back-end web server.

{{{ Andy