I have a couple routers I am practicing with for the CCNA. I don't have serial links or cables to connect them so I'd have to use ethernet cables. However no matter what I do the two routers will not ping. I've made sure ip and subnet were correct, I make sure duplex and speed were the same on both. I also turned keepalive off on both. show ip interface brief shows "up, up", but they still can't ping. Am I missing something? I have two old Cisco 1800 routers. Please let me know if you need anything else, help is much appreciated!