External access through firewall to web portal Spotfire 7.5

I'm curious if anyone who is using Spotfire 7.5 accessing the web portal (the "Landing Page") externally from the internet.  I have a Microsoft Threat Management Gateway (TMG) server, and set up an external web listener that redirects external requests to our internal network and to the Spotfire 7.5 Server.  (Configured to use HTTPS by the way with no issues internally, and external access works in part.)

When accessing the Spotfire web portal internally via HTTPS we have no issues.  When accessing https://servername.<ourdomainname>.com  the users are directed to a logon page at the URL https://servername.<ourdomainname>.com/spotfire/login.html?targetUrl=%2F... .   Once the user logs on (again while on the internal office network) they are then directed to https://servername.<ourdomainname>.com/spotfire/wp/startPage#/libraryBro... to the "Library".

However, when accessing the site externally, through the TMG firewall, when the user goes to https://servername.<ourdomainname>.com  the user gets to the logon web page as expected.  Upon logging on the user is redirected to the "Landing Page" - not the "Library Browser page"- at the URL https://servername.<ourdomainname>com/spotfire/#/landingPage  Further, the Landing Page is simply a gray page, none of the icons or links appear on the Landing Page as they would from internal network.  Now, from externally if I type the whole URL to the Library Browser page: https://servername.<ourdomainname>.com/spotfire/wp  then I can access the Library Browser page from externally, but I don't get redirected there automatically as I do when logging onto the page internally.  Ultimately we'd prefer users just get redirected to the "Library Browser" page and not the Landing Page at all when accessing externally, just as they do when accessing the web portal internally.

Using Fiddler from external, I see a "thirdparty" javascript that will present a "syntax error" at points in the process that this redirection would appear to occur.  Internally those syntax errors do not occur in the javascript.  Support could not give me any hint or direction on perhaps header issues, MIME types.  They suggested a port configuration issue however the firewall logs show "allowed" throughout the external access process so I don't see this as a port configuration problem.

So, I'm curious if anyone has ever run into a similar experience when setting up external access through a firewall.  If any special rule configuration was required. 

(2) Answers