# MAC Address



## cgigeek (Nov 14, 2013)

Besides ifconfig, is the MAC address stored physically anywhere on the server?


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## cgigeek (Nov 14, 2013)

Found it in /var/log/dmesg.boot.

Thanks for looking.


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## wblock@ (Nov 14, 2013)

The MAC address is part of the firmware for each Ethernet address.


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## trh411 (Nov 14, 2013)

The MAC address is not "stored" in `ifconfig` or `dmesg`. `ifconfig` and `dmesg` are commands, and only report information stored elsewhere. 

A MAC address is a unique identifier assigned to network interfaces for communications on a physical network. MAC addresses are used as a network address for most IEEE 802 network technologies, including Ethernet. MAC addresses are typically assigned by the manufacturer of a network interface controller (NIC) and are stored in its hardware, such as the interfaces's read-only memory or 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). A MAC address can also be "programmed" onto the NIC by a host device to use an arbitrary address, but that's a whole other topic.


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## ShelLuser (Nov 14, 2013)

Be aware that dmesg.boot only displays the situation as it was during boot. Many network interface cards ("NICs") provide a dynamic MAC address, as such you can't fully rely on the log file to show you the current configuration.

The best way to look up a MAC address is by using ifconfig: `ifconfig vtnet0 | grep ether`, where vtnet0 should obviously be replaced with the name of your NIC.


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## kpa (Nov 14, 2013)

This thread has great bikeshed potential.


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