Configuring Apache to be a forward proxy
First enable the proxy and proxy_http modules:
sudo a2enmod proxy
sudo a2enmod proxy_http
Then use this configuration to make Apache act as an HTTP proxy:
<VirtualHost *:8080>
# Enable forward proxy
ProxyRequests On
# Add "Via" header
ProxyVia On
#ProxyRemote * http://...:8080 Uncomment to route requests through another proxy
<Proxy *>
Order deny,allow
Deny from all
# Allow access only from local network
Allow from 192.168.1
</Proxy>
# Enable caching proxy
CacheRoot "/tmp"
CacheMaxExpire 24
CacheLastModifiedFactor 0.1
CacheDefaultExpire 1
ServerName my-proxy
ErrorLog "/var/log/apache2/proxy-error.log"
CustomLog "/var/log/apache2/proxy-access.log" common
</VirtualHost>
Also read this.
Tips
You can use mod_rewrite to rewrite requests. To rewrite root (/) to /temporary_outage you could use the following rewrite:
RewriteCond %{HTTP_HOST} ^(www\.)?xxx\.com
RewriteRule /$ http://%{HTTP_HOST}/temporary_outage/ [P,L]