Struts,fileupload,blocked

[hahahui]

I use the struts file upload to upload the content file.
When using in the intranet,it works fine,but in the internet,the uploading process is blocked and my action is never called,what's wrong.

JDK:1.4.1
JBoss:3.2.2
Struts:1.1

Thanks

[mikefinn]

Not to oversimplify, but is it possible that you have a firewall blocking POSTs or some other means of blocking a file upload?