There are 4 Apple computers (iMac, MacMini, MBPro and a PowerBook) all in a home network, 2 wired Ethernet (iMac, MacMini) connected and 2 on wifi. The other day a friend came along with his laptop pc and wanted to share the internet connection. So this is what i did with strange results, i put the iMac on wifi and took its Ethernet cable and plugged it on my friends laptop. After a few minutes all computers had lost their connection with the router! To fix this i had to reset the router! What did i do wrong, is it a matter of ip conflict? And how can i fix this so when one comes along with his computer i can share the internet with him without issues!