Parsing a (complicated) URL

This is a tricky one that requires a level of Excel function mastery I don't currently have. I have been studying Excel's site for way too long and I'm still not progressing.

I am trying to take a complicated URL like:

http://dp18776.live.domiain.net/active/MO_Mi_WFM

and parse it so that I get this:

live.domain.net

The closest I have gotten is with this:

http://dp18776.live.domiain.net

My logic:

=LEFT(A17, SEARCH(".net",A17)+3)

The reason I can't stop there is because the local part can be variable across the thousands of records, whereas only the domain is (e.g. live.domain.net) constant.

I also know I need to use the MID function, I was testing what I could get away with on more basic functions, but the bigger wrench in the works is that I need to be able to key off ".net" to retrieve the domain, so I need to set the starting point in MID() as ".net" - len(domain)

Would anyone be able to help me complete this formula?