From Wikipedia and I concur.
MAC addresses are most often assigned by the manufacturer of a
network interface controller (NIC) and are stored in its hardware, such as the card's
read-only memory or some other
firmware mechanism. If assigned by the manufacturer, a MAC address usually encodes the manufacturer's registered identification number and may be referred to as the
burned-in address (
BIA). It may also be known as an
Ethernet hardware address (
EHA),
hardware address or
physical address. This can be contrasted to a programmed address, where the host device issues commands to the NIC to use an arbitrary address.
A
network node may have multiple NICs and each must have one unique MAC address per NIC.
MAC addresses are formed according to the rules of one of three numbering name spaces managed by the
Institute of Electrical and Electronics Engineers (IEEE): MAC-48, EUI-48, and EUI-64. The IEEE claims
trademarks on the names EUI-48 and EUI-64, in which EUI is an abbreviation for
Extended Unique Identifier.
Your router maps the NIC MAC address to an internal IP address similar to the following ARP table:
Note
a MAC address usually encodes the manufacturer's registered identification number and may be referred to as the burned-in address (BIA). It may also be known as an Ethernet hardware address (EHA), hardware address or physical address.
Sure you can change it. Just reef the chip out and solder in a new one.