User Gets Blank Screen in Portal Services
Articles and Tips: qna
01 Feb 2003
Q.
When various people at our company try to log in via Novell Portal Services (NPS), they are presented with a blank screen. Any ideas why this is happening? We are using NPS, iChain, NetWare 5.1, Apache and Tomcat.
Being Blank in Bassein
A.
Dear Blank: You are lucky that Novell's Technical Support Group has seen this problem. In fact, they have reproduced the problem in their labs. Their environment consisted of the following:
The iChain v2.0 box on DMZ with the public DNS entry (162.x.x.x) for xxx.yyy.com bound to the interface. An accelerator was configured to provide content from the NPS server that was located on the internal network of 10.0.3.12.
NetWare 5.1 Support Pack 3 server configured with Apache and Tomcat, with the local IP address bound to the local ethernet interface.
RESOLV.CFG on this server is pointing to the BorderManager (BM) server that provides DNS proxy services. Pinging the xxx.yyy.com host resolves to the public IP address of the iChain device (162.x.x.x).
There are two scenarios that can be analyzed:
Scenario 1. After starting Tomcat, a user opens his browser (that is configured to use the BM proxy with Client Trust) and enters http://xxx.yyy.com. They are presented with the iChain authentication page, where they fill in their credentials and are redirected to the NPS server. The tomcat log screen shows the reading of gadgets and configuration information, including the copying of gadgets from the other NPS server that is configured for load balancing and fault tolerance. After a few seconds, the user still has a blank screen.
Scenario 2. If the first user to hit the portal after startup uses http://10.0.3.12/ with a browser that is configured to not use the proxy, the portal displays the correct page once the user has authenticated. If the user then uses http://xxx.yyy.com/, the correct pages are displayed.
So to fix this problem, add a HOSTS file entry on the NPS server for the public DNS name of the service portal.ema.com that is pointing to the private IP address. Then when NPS attempts to retrieve the style sheets using the client-provided HTTP host name (portal.ema.com), the resolution of this address would be to the server itself instead of the server trying to get to itself via iChain, as was originally the case. (See TID #10069019 entitled "Blank Browser Screen when Logging In via Novell Portal Services" for more information.)
* Originally published in Novell AppNotes
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