Different behavior observed when diff. IE proxy setting options us

[Guest]

I have a web application developed by Corporate development team. The
"upload" function of the web application to transfer file from the user's XP
to the application server behaves completely different when different IE
proxy setting options are used.

(1) When "automatically detect setting" of IE is being used.
The "upload" function will fail and the IE will return following error
" The page cannot be displayed
HTTP 500.100 - internal server error - ASP error Internet Information
Services
Eror type: Microsoft VBScript runtime (0x800A0005)
Invalid procedure call or argument: 'MidB'
/abc/xyz/xyupload.asp, line 102"

(2) When manual proxy of IE is used and the ISA proxy server's FQDN and port
number are entered manually into IE. Then the "upload" works normally
without problem.

I'm using ISA E.E 2006 with integrated NLB.

Both the XP PC and the application servers are internal hosts, the domain
suffix and ip subnet of the XP PCs and application servers have already been
defined as Internal network in WPAD.DAT and on ISA server side.

Moreover, I have used the ISA Live Log to capture the communication
originated from the XP PC, whereas, nothing has been captured about the
communication between the XP PC and the application servers. This means the
ISA server treat both XP PC and the application servers as internal hosts,
thus the communcation traffics didn't passing via the ISA server.

It seems tha the web application behaves completely different when different
proxy setting options of IE are being used.

Could anyone tell what is wrong?

 

[Rob ^_^]

Hi Terence,

The server error message indicates that the MidB function is failing with an
invalid argument... presumably a zero length string (url to the file to
upload?)

It would appear that your server is blocking traffic originating from
specified ports. I had a recent problem where I could not send emails to my
my mail server because my ISP was blocking port 25 (to prevent bulk email
spaming).

Hope my guess helps.

Regards.