So let me try to understand this: You have a domain, let's call it myWiki.com
, and this is set up so that any visitor that goes to this domain is redirected to, let's say: myDom.com
.
Meaning, at this point, visitors see "myDom.com
" in their browsers' URL field.
What you want to achieve is that their browser shows "myWiki.com
" instead, even though they are actually browsing on myDom.com
.
I'm sure if you think about it you will realise that if that was possible, this would be a rather big issue, as I could then have a server under myevilsearchengine.com
and pretend to the users that they are actually on google.com
. Not good.
There are some ways around it - namely people found that they can use a frameset to keep one domain name visible, while the user views a different one. But that would mean that whenever the user clicks on a link, that illusion would be broken. Also they could not get the real URL of the page, thus you would never get usable backlinks. This all leads to search engines penalising you for playing such dirty tricks, up to the point where your servers may get blacklisted. In other words: don't do that!
What you can do, however, it set up your second domain to be used as an alternative to the first, so that the same server is used for both. That is something your hosting provider has to do for you, though, and this is outside of the scope of this forum.
In any case, better change your baseurl setting back to the actual domain of the wiki. This is not the right place for these kinds of configurations.