SnipSnap can run without Apache, but if you must use Apache and Apache uses port 80 you can use Apache as a proxy

• SnipSnap can run without Apache, but if you must use Apache and Apache uses port 80 you can use Apache as a proxy.
• Install SnipSnap as explained above. Leave the Port somehwhere above 1024 (default is 8668).
• Edit your apache httpd.conf (enable mod_proxy):

# Enable mod_proxy (uncomment the LoadModule line!)
# Both works in apache1.x and apache2.x
LoadModule proxy_module /usr/lib/apache/1.3/mod_proxy.so
# Uncomment the AddModule line for mod_proxy.c
# Only in apache1.x,in apache2.x,you did not need this line
AddModule mod_proxy.c
# make sure you don't allow anyone to use your apache as proxy
ProxyRequests off
# use apache as a reverse proxy to your [SnipSnap] server:
# my.snipsnap.host and path are what you entered during installation.
# The host my.snipsnap.host can be a fully qualified domain name or an IP number.
# The path is the relative path to your snipsnap directory from your web server 
# root directory. If you placed the snipsnap folder at the root level you 
# don't need to specify the path. 
# If you left host empty during installation enter localhost as the host.
ProxyPass             /snipsnap/       http://my.snipsnap.host:8668/path
ProxyPassReverse      /snipsnap/       http://my.snipsnap.host:8668/path

Now your can use your SnipSnap on your apache web server: http://your.server.com/snipsnap/

ATTENTION: If you use multiple SnipSnap applications make sure you let them run on different ports as apaches mod_proxy can't get the cookies right.

ATTENTION: Be careful with the slashes. /snipsnap/ http://my.snipsnap.host:8668/path/ should work. In other cases you would create a neverending redirection cycle (pmode);if you can't get it work by configure the proxy by following above steps;try "/snipsnap" instead of "/snipsnap/".

ATTENTION:__Do NOT forget to enter the administration interface to set the context path to "/snipsnap" or other words you like, but it should be corresponding with what you set in the httpd.conf.

Securing SnipSnap using VirtualHost/SSL with Apache

This example assumes you have configured the SSL engine, loaded the mod_proxy and mod_access. It is even possible to use mod_pam (see apache docs).

<VirtualHost my.snipsnap.domain:443>
  ServerName    my.snipsnap.domain
  ProxyVia      full
  ProxyRequests off
  NoCache       *
  ProxyPass             /       http://internal.server:8668/
  ProxyPassReverse      /       http://internal.server:8668/
  <Directory proxy:*>
    AuthType Basic
    AuthName "SnipSnap VPN Access"
    AuthUserFile /etc/apache/snipsnap/mysnipsnap.users
    #AuthGroupFile /etc/apache/snipsnap/mysnipsnap.groups
    Require valid-user
  </Directory>
</VirtualHost>
<VirtualHost cbe.first.fraunhofer.de>
  RedirectMatch ^/(.*) https://my.snipsnap.domain/$1
</VirtualHost>

If you don't want SSL, remove the port ":443" and the second VirtualHost entry。

from http://snipsnap.org/comments/Apache+as+Proxy#comment-Apache%20as%20Proxy-41

related post: http://briteming.blogspot.com/2011/12/jspsnipsnap.html