Okay, network theory and protocol questions for you guys:
Assuming a router is using NAT, is a device's MAC address every actually exposed to the Internet? Or, does the router transmogrify (wow, spell-check didn't have a problem with that word, I always thought it was just a Calvin and Hobbes term) the MAC like it does with the source device's IP address?
I seem to remember from classes that once the packet hits the network router the router substitutes its IP and MAC info in there, slaps a frame on it and then kicks it out onto the web in the general direction of the closest IP match. However, a thread that I read on another site indicated that the MAC address changed with every hop!
While that may be nice for privacy issues (no real way to tell what the original device/routers MAC was from an arbitrary point along the hops), it doesn't really seem to make sense that both the IP and MAC would need to be stripped each time.