Hello, We are currently setting up a site at a second domain, lets call it seconddomain.com that we want to eventually integrate into our main domain. The main domain is very old, classic asp, so we're not ready to integrate yet. We want the domain to be rewritten to this:

seconddomain.com/inspiration-gallery/

to

maindomain.com/inspiration-gallery/

Can someone provide me instructions on how to do this efficiently? I'm new to this aspect of dev, so keep it simple if possible. I'm hearing terms like "reverse proxy", "pass through" in other circles, all of which is new to me.