But I would have tried two machines with the same MAC on the same LAN for this test. Lookup MAC SPOOFING or "SMAC" to do your test.
I didn't get a clear picture of what you did with the routers but they may have not been on the same LAN.
While in my Secuity + class the following question was asked. "If I am using MAC filtering on my personal wireless network how can I tell if someone has cloned one of my trusted MAC's and entered my network" This was asuming someone was able to decrypt the WEP/WPA or none was used. If anyone has any input on that question it would be great.
The following question was derived from the last question, "Can two network devices function on the same network, with the same MAC address?" This was a question I felt I could return to my room and test, so I did with the following set up:
1 WRT600N with a wan connection to Charter ISP. the WRT600N had two WRT54G routers connected to its lan.
192.168.1.20 and 192.168.1.21 was set up static to each of the WRT54G routers WAN respectivly. 1.20 had a lan of 192.168.2.1 and 1.21 had 192.168.3.1. Each WRT54G had one machince connected to it using DHCP. In each of the WRT54G routers, using the clone MAC option, each routers MAC was set to 22:22:22:22:22:22 . From each machine connected to the two WRT54G's yahoo.com was pinged with -t. Each machine was able to ping the same yahoo.com ip address as the same time with 1% failure rate for about 20 mins. One ping was stoped and reset to ping google.com with the same results.
This was something our instructor said couldn't happen. My thoughts on it were maybe/maybe not, I am under the impression routers route by IP address and Switches use MAC addresses to route? I then placed a Linksys 5 port workgroup switch in between the WRT600N and the two WRT54G's, with the same results. Ok, maybe this Workgroup switch is actully just a smart hub, so I changed it out with a WRT310N, turning off wan connection, giving it a local ip address of 192.168.1.19, and disabled dhcp server. (I used the LAN ports not the WAN) I did this in hopes of trying to make it somewhat function like a managed switch not sure if that happened or not but none the less I got the same results, both machines were able to ping out at the same time, there for two identical MAC addresses on the same network.
Is there any flaws in how I tried to test this question? Did the WRT310 function like a managed switch would / if not is there anyway to set it up so it would? Any additonal input or thoughts or things I should know about how routers and switches work/route that would help me understand it a little better? Each device has DD-WRT loaded, would linksys firmware give me different results?