ISA 2006 and Status: 64 The specified network name is no longer available

Recently someone reported that a banner ad they wanted posted on a page was not showing up internally, although it did when viewed from their home. The banner ad was a hyperlinked picture - snagged from an external site. What was happening internally was that the image simply did not appear, although the rest of the page rendered fine and the call to the remote site's page (wrapped in a javascript script tag) was in the page source.

When I tried to open the specific page I received a error status 64 - The specified network name is no longer available.

Suspecting that the blockage was caused by ISA, and also suspecting that the blockage might actually be a good thing, I loaded fiddler on a outside client and tried to access the page. Sure enough, fiddler (once again) came through. The issue? In the words of fiddler 'This buggy server did not return headers.'

The issue is that whoever was returning the code stripped out all headers. While browsers will let that pass, ISA will block it.

The solution? Fix those darn headers!!!!