IISPROXY or IIS truncate long URL's

Question

The following URL responds with the page cannot be found(create web shop user) in EP6 NW04 SP12 on Web AS 6.40 SP12 with CRM Java Web Apps for Internet Sales SP8 when it is passed via IIS+IISPROXY as the intermediary.
http://www.customer.com:8080/irj/servlet/prt/portal/prtpos/pcd!253aportal!255fcontent!252fcom!252eao!252ebrother!252fcom!252eao!252edesktop!252fdealer!255fdesktop!252fframeworkPages!252fframeworkpage!252fcom!252esap!252eportal!252einnerpage!7b!3b1!7d.com!252esap!252eportal!252edetailedNavigationTree!7bHideMode!7d_com!252esap!252eportal!252edynamicNavigationArea!7bHideMode!7d_com!252esap!252eportal!252etargetsiView!7bHideMode!7d_com!252esap!252eportal!252etargetsiView!255f!7bHideMode!7d-/prttarget/com!252eao!252ebrother_internal_user_registration.content/prteventname/HtmlbEvent/prtroot/pcd!3aportal_content!2fcom.ao.brother!2fcom.ao.desktop!2fdealer_desktop!2fframeworkPages!2fframeworkpage!2fcom.sap.portal.innerpage
A trace shows a POST with result 400.
Replacing :8080 with the direct port of the portal (:50000) results in the correct page being displayed.
IIS and or IISPROXY are affecting the URL.
Note 734462 has already been implemented to increase the size of url segments to 65535 and the server rebooted.
Looking at the iisproxy.log file, there is no activity during the failed attempt that leads me to think IIS (6.0) is the culprit.
Great clues gratefully rewarded !

Answer 1

Raul,
in the first place see SAP Note 734462.
In our case this is caused because the generated URL 'double encoded' and is rejected by IIS (it suspects it is being hacked) before it even hits IISPROXY or the J2EE. The web server in J2EE does not care about the syntax of the URL whereas IIS does. SAP are investigating this problem internally and have identified the offending code deep in the portal runtime engine but have not published the fix (it will probably arrive in a future SP)  - however, there may be a work around (worked for us) that you might use. We had to change the isolation method of the iView from embedded to URL.
We were also advised by SAP to downgrade our IISPROXY version, we are now using version 1.6.
And a word from SAP -->
"Finally, please note: as current SAP recommendations, it is advised to use IisProxy only in case of NTLM authentication. If you do not use
NTLM you should replace the IisProxy with the WebDispatcher, which is
the successor. Check the note 886214 for details."
Or as I have done in some cases, switch to Apache 2.0.55 instead of IIS (unless you need NTLM integrated authentication).