I am sorry to say (mydnight) that what you are attempting is not ever going to work using these tools.

The problem is that you have a single IP address visible to the rest of the world, and attempts to connect either to www.myserver.com or to mail.myserver.com will both turn into a TCP connection on xxx.yyy.zzz.foo:80. Then, your httpd accepts the connection, reads the Header info from it, and matches the server named in the header to one of your <VirtualHost> containers. So far, everything is fine.

However, when you attempt a permanent redirect to 192.168.0.2, the jig is up. A redirect header is sent back to the browser, who attempts to contact the given address. That address, however, is not permitted on the public Internet. Any public router worth its salt will unceremoniously drop any packet addressed to a Private Networking address, disrupting your attempted redirect.

The simplest way to make this work is to buy a second IP address, and arrange for mail.myserver.com to resolve to the second address. Then you can use iptables to translate the second external IP into the internal address of your Zimbra box. This might not, however, be the cheapest, since you will have to pay your ISP for a second address.

Sorry about your problem, mydnight. I solved my problem by backup my data and reinstall. I didn't do anything different, at least to the best of my knowledge, and it didn't happen again. Now I have both regular http and https for SVN running on my box. I use DynDNS to point to my router and forward to my linux box. Everything is running fine for almost one month.

However, I still don't know what caused that problem.
Good luck.

Unfortunately, the thing you are trying to do cannot be accomplished using the Redirect scheme. The problem with that is that the Apache server will send a Header: Redirect 192.168.0.2 to the requesting browser, which will then try to access a server at that address, fail, and return to the server it was originally trying to reach (your main server).

Have a look, though, at the Apache directive Reverse Proxy, whicb appears ideally suited to what you want done. It makes a proxy request on behalf of the original client, directed to a server that would otherwise be inaccessible to that client, and returns the result to that client when it arrives from the intended server.

Thanks -- I've got it fully functional now, using the reverse proxy directives