Subject: RE: Intermittent "Page cannot be displayed" and "Cannot find erro r or DNS error" using mod_ssl and IE 5.5

From: "Kuczborski, Carol L" <[email-masked]>
Date: Mon, 7 Jan 2002 17:05:31 -0500

I am replying to my own problem I posted several months ago to supply the
resolution.  I worked with Oracle on the problem since they package the
Apache Web Server and mod_ssl was packaged with their Oracle9i Application
Server.

To resolve the intermittent "Page cannot be displayed" and "Cannot find
error or DNS error" we received using mod_ssl and the Microsoft Internet
Explorer (IE) browser, we applied the following solutions provided by Oracle
for mod_ssl:

*	Implemented solution for Oracle Bug No. 1822053 (HTTP 404 Doing
Portal Development) by changing (and un-commenting) the following line in
our Apache http.conf file:
*	From:  #SetEnvIf User-Agent ".*MSIE.*" nokeepalive
ssl-unclean-shutdown
*	To:      SetEnvIf User-Agent ".*MSIE.*" ssl-unclean-shutdown
*	Implemented solution for Oracle Bug No. 1821195 (When uploading
large file using modplsql & SSL error reading data from client) by replacing
the existing ApacheModuleSSL.dll file with the patched file referenced in
the bug details. 

Applying the change to the http.conf file identified by Bug No. 1822053
(removing the nokeepalive entry) seems to have solved our problems with the
intermittent occurrences of the noted error message on most all web pages in
the application.  We still occasionally get the error messages, but not as
frequently as before.  Before the configuration change we could not access
the application for more than 2-3 minutes without receiving the error.  Now
we only get it a few times during the day.   

The second patch solved our problem with receiving the noted error message
whenever we tried to add items to a content area using the Oracle9iAS Portal
add-item-wizard.  Prior to applying the patch we always received the noted
error message each time we tried to access the add-item-wizard pages to
upload a file to the server.  According to the details for the
ApacheModuleSSL.dll patch, there was mention of a bug in the "select"
function in Windows NT 4.0:

"When checking a socket, if data can be read without blocking, select ()
returns yes, but when actually reading from the socket with recv(), that
function returns WSAEWOULDBLOCK, which says that reading would block.  It
seems that this problem does not occur in usual operation, but only in an
SSL enabled Apache (modssl or apache-ssl) with https.  The code for WIN32,
which handles writing to a socket, already contains a workaround for this.
The code for reading from a socket did not have a workaround."

Carol Kuczborski
EDS - Enabling Business Solutions
MS A6N-B47
13600 EDS Drive
Herndon, VA 20171

* phone: +01-703-742-1025 (8-432)
* mailto:[email-masked]
www.eds.com

>  -----Original Message-----
> From: 	Kuczborski, Carol L  
> Sent:	Monday, August 06, 2001 1:54 PM
> To:	[email-masked]'
> Subject:	Intermittent "Page cannot be displayed" and "Cannot find
> error or DNS error" using mod_ssl and IE 5.5
> 
> Anyone know about the following issue or steps towards resolving:
> 
> Background:
> 
> Implemented SSL using mod_ssl with the Apache HTTP Server and self-signed
> certificates.
> Server environment: Windows NT Server 4.0, Apache HTTP Server, Oracle
> 9iAS, Oracle 9iAS Portal, port 443
> Client environment: Microsoft Internet Explorer (IE) 5.50, 128 bit
> encryption
> 
> Problem:
> 
> When accessing our Portal website using the IE browser, we get the
> following intermittent messages:
> 
> "The page cannot be displayed" and "Cannot find server or DNS error".
> 
> We know it has noting to do with a DNS error, because the pages can be
> accessed using the Netscape browser.  Sometimes the page can be accessed
> by the IE browser, and at other times we get the error.  Occasionally a
> reload, refresh, or back and forward, will return the page, and at other
> times we get the error.  Everything works fine using the Netscape 4.75
> browser, we never et the error.  We think it is the problem noted on the
> FAQ page about " Why do I get I/O errors with MSIE clients" and made the
> recommended change, but it did not work.
> 
> Any suggestions would be appreciated.  We must use SSL and IE.
> 
> Carol Kuczborski
> EDS - Enabling Business Solutions
> MS A6N-B47
> 13600 EDS Drive
> Herndon, VA 20171
> 
> * phone: +01-703-742-1025 (8-432)
> * mailto:[email-masked]
> www.eds.com
> 
> 
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