I was trying to search for answers and browse the sharing settings but the network and server jargon doesn't make any sense to me. I guess I'll just have to ask from you guys. The situation: So I have two macs that I wish to use simultaneously with the same mouse+keyboard. I found a way to share the sound and I've done screen sharing before. But now I live in a place where I'm not the only user of this wifi, so I'm not feeling so good about doing screen sharing wirelessly. I managed to establish a closed connection between the two by "Create network", but it's a shame that it cancels out the access to internet. My iPad has 4G and iPhone has 3G, but apparently the operators don't allow tethering. These computers have been connected before, and they can see one another in the network when in the same wifi. To my horror, I realized that I can access the files without any passwords so either the files were unprotected or I had granted some password protected access before and it's still using it. For now I shut down all sharing from both computers but I'm still not feeling completely safe because I have no idea what others can or can't see. I'm a complete dummy with the network jargon abbreviations. If there's no other way but to fiddle with those settings, some newbie-friendly reference would be highly appreciated. The problem summarized: How should I share files and screen between my two computers securely without losing the access to internet from at least one of them? If I buy an ethernet cable to connect the computers physically, does it cancel out internet access like private wireless network does? Is there any way how I could reliably monitor what other computers can see and access when my computers are in the same wifi network?