Gandalf is on the right track as we can’t do much to help without knowing what you’ve done to create your redirection … and what type of server you are using (Apache vs IIS).
If it helps, it appears that you have created this massive problem for yourself as your website should be in xyz.com’s public_html directory (your DocumentRoot) so no redirection would be necessary.
If you need to bury your website several directories down from your DocumentRoot, you could use a symlink to effect a redirection. My expertise, though, is in using Apache’s mod_rewrite to make my redirections and, in your case, would require you to make all your internal links to the DocumentRoot and then fetch the files from 123/Web/Webpages/Main via redirections … VERY ugly and unnecessary, IMHO.
Are you using PHP to redirect? If so, that’s why it shows the actual page you’re on. As @dklynn says, your best bet is to use Apache’s mod_rewite