You are going to want to use the referrer.  This site might get you 
started: http://borkweb.com/story/apache-rewrite-cheatsheet
If you need more info, check apache's docs or hit up your search engine.
The other option is to use apache's virtual hosting and separate the 
sites out from the start; then put the rules in the config file instead 
of relying on htaccess.

Cheers,
Mark

Michael Mansour wrote:
> Hi,
>
>   
>>> I realise this may not be the best mailing list for this query, but if someone
>>> knows...
>>>
>>> The problem I have is, I have an Apache website running on:
>>>
>>> http(s)://site.example.local
>>>
>>> For my local subnet (which exists in .local), I have Apache setup to do:
>>>
>>> Redirect / https://site.example.local
>>>
>>> for http (port 80) connections, so when anyone types http://site.example.local
>>> on the .local subnet they're redirected to the SSL website.
>>>
>>> When accessing this site externally on port 80, I go to:
>>>
>>> http://site1.example.com
>>>
>>> and (via DNS and PAT rules on the firewall) get:
>>>
>>> https://site.example.local
>>>
>>> as the URL in the external Web browser, which obviously doesn't work. This
>>> makes sense though because of my "Redirect / https://site.example.local entry"
>>> in Apache.
>>>
>>> How can I configure Apache to keep:
>>>
>>> Redirect / https://site.example.local
>>>
>>> for the .local subnet, while:
>>>
>>> Redirect / https://site.example.com
>>>
>>> for external subnets?
>>>       
>> First, can you confirm that https://site.example.local works locally
>> and https://site.example.com works externally (I suspect that you 
>> will need two certificates) ?
>>     
>
> Yes this works fine. The site.example.local is actually a PHP Help desk app,
> so we use this internally every day (on https://site.example.local) and our
> customers check the progress of their cases externally via
> https://site.example.com
>
> The problem is when customers forget to enter the https and enter http, we'd
> just like it automated for them when they make a mistake in the URL.
>
>   
>> If the content is the same, can you redirect everyone to 
>> https://site.example.com ?
>>     
>
> Yes the content is all the same but since PHP app is running on a server on
> our local network (in our office) and listening on a Virtual IP on the
> internal network, then we cannot visit http(s)://site.example.com from our
> local network.
>
> The way the external people get to it is by giving the site.example.com an A
> record which points to a dedicated WAN IP and a PAT rule on the firewall to
> forward port 80 and 443 traffic to the internal Virtual IP.
>
> In summary, you cannot go to your external WAN IP from your internal local
> network.
>
> So I need a way to tell Apache that if the visitor is coming from the WAN
> (internet) then Redirect to https://site.example.com, if they're coming from
> our local network then Redirect to https://site.example.local
>
> I've search the web and so far haven't been able to find a way to do this.
>
> Regards,
>
> Michael.
>
>   
>> -- 
>> Dr. Andrew C. Aitchison		Computer Officer, DPMMS, Cambridge
>> [log in to unmask]	http://www.dpmms.cam.ac.uk/~werdna
>>     
> ------- End of Original Message -------
>
>   


-- 
Mr. Mark V. Stodola
Digital Systems Engineer

National Electrostatics Corp.
P.O. Box 620310
Middleton, WI 53562-0310 USA
Phone: (608) 831-7600
Fax: (608) 831-9591