Particular websites blocked when using Internet Sharing
Have you tried connecting to these sites directly with the iMac whose internet connection is being shared jb1785?

I've had some very bad luck with trying to share internet connections (I was trying to share a VPN from a MacMini to an Apple TV or Samsung BluRay player. Not easy, not high performance and not reliable.



What do work brilliantly are those little white Apple USB Ethernet Adapters (I'm assuming you don't have Ethernet on that MacBook Pro or you'd be using it). Buy the Apple one as others are either clunky or unreliable (very occasional system crashes but occasional is too much). Bringing in a second Ethernet cable should be easy but if it's not you could drop a small ethernet switch in front of the iMac for very little money for 100 BaseT and not much money for 1000 BaseT.

Daisy chaining sounds like a good idea but you are exponentially increasing your chances for nagging network issues and losing time.