Behind the Oracle HTTP Server - OHSThe OHS is the abbreviation for the Oracle HTTP Server. This is the core component for the client facing interface of Oracle Applications. Much of how Oracle Applications behaves is controlled from the OHS.The OHS is built upon the Apache Server project. The Oracle Application server in Oracle Applications 11i (11.5.10.2) is based on Apache 1.3.Oracle Application Server 10g Release2 is based on Apache 2.Though we do not have 10g release 2 application server by default in 11i, we can choose to implement the 10g applications server with 11i.You can find out the current version of OHS by the command httpd -version $ httpd -versionServer version: Oracle HTTP Server Powered by Apache/1.3.19 (Unix)Server built: Apr 5 2004 16:17:45 (iAS 1.0.2.2.2 rollup 4)There are some core files which control the behavior of the Oracle HTTP Server. Again most of these files are autoconfig managed , so changes to them should be via the Oracle Applications Manager and autoconfig must be run to propagate these changes to the respective config files.httpd.confThis is manin config file for the Apache based OHS. It contains all vital configuration information for the OHS like the port on which the server is running, the portocol used etc.A detailed list of derivates supported by the httpd.conf file can be found in the apache documentation. Again as mentioned before this file is also autoconfig managed.httpds.confThe httpds.conf file is similar to the httpd.conf. The httpds.conf filers comes into use when apache runs in the Secure Sockets Layer implementation(SSL).Another way make sure if httpds.conf is being used in your environment or not is to open up the apachectl file in the Apache/bin directory and check if the httpds executable is being used along with the httpd executale. something similar to belowHTTPD=/d01/sam/samsora/iAS/Apache/Apache/bin/httpdsaccess.confThe access.conf file is natively used to specify the acess control files for the HTTP server. But in Oracle Implementation of Apache server this file is essentially kept empty and instead the AccessConfig directive in httpd.conf is used.url_fw.confThe URL firewall or the url_fw.conf file implementation is used to provide an additional layer of security on the external tier.This file comes into play once you define a node as external. After this is enabled only the urls specified in the url_fw.conf files will be accessible through the external tier in a DMZ architecture.Once enabled the httpd.conf file will have a link to include this file.security.confThis file contains the security configuration for the OHS.It has information regarding security auditing and also location of the security audit log file location.oracle-apache.confThis a file that stores the configuration information for various supported modules in Oracle applications like imeeting , OEM etc.It will contain entries to include these configuration files. These module specific configuration file like the imeeting.conf will also reside in the Apache/conf directory on the application server.

Where are the Log Files located in R12

For DBA’s who mostly worked on 11i environments, finding the log files (Concurrent manager log, apache log etc.,) on a R12 environment might pose a threat initially, because these log files no longer reside in their old location ie., $APPLCSF/$APPLLOG or $APACHE_TOP/Apache/logs.
In R12, the log files are located in $LOG_HOME (which translates to $INST_TOP/logs)
Concurrent Reqeust related logs
$LOG_HOME/appl/conc -> location for concurrent requests log and out files$LOG_HOME/appl/admin -> location for mid tier startup scripts log files
Apache Logs (10.1.3 Oracle Home which is equivalent to iAS Oracle Home)
$LOG_HOME/ora/10.1.3/Apache -> Location for Apache Error and Access log files$LOG_HOME/ora/10.1.3/j2ee -> location for j2ee related log files$LOG_HOME/ora/10.1.3/opmn -> location for opmn related log files
Forms & Reports related logs (10.1.2 Oracle home which is equivalent to 806 Oracle Home)
$LOG_HOME/ora/10.1.2/forms$LOG_HOME/ora/10.1.2/reports
Related metalink notes to enable additional debugging
419839.1 - How to enable Apache, OC4J and OPMN logging in Oracle Applications R12422419.1 - R12 - How To Enable and Collect Debug for HTTP, OC4J and OPMN