Redirects and masking with Apache
For that, you'll want a reverse proxy:
ProxyPass /path/ http://128.10.10.10/
ProxyPassReverse /path/ http://128.10.10.10/
When you do this, you'll no longer redirect traffic to 128.10.10.10. Traffic will flow through domain.com to 128.10.10.10. The 128.10.10.10 web process will see the traffic coming from domain.com, not from the end-user.
You can read more details at Apache's mod_proxy documentation.