Installing standalone HTTP server(w/11gDb,3.2ApEx) & architecture questions

Question

Hi,
I'm a newbie to ApEx and am in the process of laying down ApEx infrastructure (11g DB w/ 3.2 ApEx).
Since we want to have the database server behind the firewall, one of the options is to set up 3-tier architecture (ie: DB server, Oracle HTTP server, and user's web browser) ALL on separate hosts. However, it appears all the ApEx installation guides (11g DB w/ 3.2 ApEx) ONLY mention about installing DB/ApEx together with OHS on the same host (ie: OHS is distributed with Oracle 11g, OHS is installed in an Oracle home...etc). This is NOT what I want. Please note that ApEx automatically installs with Oracle db 11g or later.
Q1) Where can I download OHS, NOT bundled together with 11g? Does 10g HTTP server work with 11g DB?
Q2) What's the procedure of setting up OHS on its own host (so that the host can be outside of the firewall)?
Q3) My understanding is that ONE ApEx with ONE database (ie: ApEx resides inside the database). Can I have ONE ApEx pointing to MORE THAN ONE database?
Q4) My understanding is that ApEx is covered under database license, regardless of whether OHS resides in same host of the db server or not. Correct?
Q5) My understanding is that basically I have 2 options of setting up the fore-mentioned scenario OHS as follows:
Option#1: Using the 3-tier architecture or
Option#2: setting up OHS together with database in the same host, but use Proxy server
Which one is the best practice? Pro's and con's?
I also searched on this forum, but it does not appear to have answers to my questions.
Your expertise and insights are appreciated :)
Helen

Answer 1

Thank you, Varad for your prompt reply.
3 more questions:
Q1)
Database + APEX + OHS on server 1 (within the firewall)
Apache 2.2 in the DMZ - serves static pages, non-APEX apps and forwards requests to APEX applications to the OHS running on the db server.Say I have a production db + ApEx + OHS on prod_server, and a test db + ApEx + OHS on test_server, should I have ONE Proxy server for BOTH production AND test, or each environment should have its own proxy server? The SA said that we "should" have one for each and can be on virtual machines but on the same physical host. What's your take on it? From what you mentioned, you folks seem to run everything together within the same Apache web server. But if I make a configuration change (say, in "httpd.conf"), and I need to reboot the Apache web server to take effect, then all the services will be affected, correct?
Q2)
I suggest you first get your database and APEX configured and working correctly and accessible from the OHS. You then install Apache on your DMZ box(download from http://httpd.apache.org) and configure it forward requests destined to the APEX application to the back end OHS. At a minimum your Apache config fille will have entries similar to (assuming external users enter the URL http://www.acme.com/apex to access the APEX applications)
ProxyRequests Off
ProxyPreserveHost On
ProxyPass /apex http://Oracle_HTTP_server:8080/apex
ProxyPassReverse /apex http://Oracle_HTTP_server:8080/apex
.....After the above change, what needs to be included in ApEx Application Builder -> Application xxx -> Shared Components -> Proxy Server -> ?
The "ServerName" in the VirtualHost section?
Q3) Currently I'm on ApEx EPG. And I know that Oracle is pushing towards EPG. But it appears that it's a GOOD idea to move to OHS instead of using the embedded gateway for several reasons. One of them is that it does not seem (or I could not find) the typical Apache configuration file ($ORACLE_HOME/Apache/Apache/conf/httpd.conf). What's your take?
Thanks much again :)
Helen