Q. Can you tell me how can I find out MAC address under Linux or FreeBSD server?
A. A mac address is acronym for media access control address, is a unique address assigned to almost all-networking hardware such as Ethernet cards, router etc. Most layer 2 network protocols use one of three numbering spaces managed by the IEEE: MAC-48, EUI-48, and EUI-64, which are designed to be globally unique. (see mac address at wikipedia for more information).
Following command work with Linux and other UNIX oses:
ifconfig command
Ifconfig is used to configure the kernel-resident network interfaces.
In order to find out MAC address of system you can use ifconfig command as follows:
$ /sbin/ifconfig | grep HWaddr
Output:
eth0 Link encap:Ethernet HWaddr 00:0F:EA:91:04:07
OR
$ /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr 00:0F:EA:91:04:07 inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20f:eaff:fe91:407/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:60400 errors:0 dropped:0 overruns:0 frame:0 TX packets:109216 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:69273219 (66.0 MiB) TX bytes:14285799 (13.6 MiB) Interrupt:18 Base address:0xc000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:3869 errors:0 dropped:0 overruns:0 frame:0 TX packets:3869 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:396498 (387.2 KiB) TX bytes:396498 (387.2 KiB)
OR as a root user type following command:
# grep eth0 /var/log/dmesg
eth0: RealTek RTL8139 at 0xc000, 00:0f:ea:91:04:07, IRQ 18 eth0: Identified 8139 chip type 'RTL-8100B/8139D' eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
FreeBSD example
# ifconfig
Output:
lnc0: flags=108843mtu 1500 inet 74.xx.yy.zzz netmask 0xfffffff0 broadcast 74.xx.yyy.zzz ether 00:0c:29:b8:92:8b plip0: flags=108810 mtu 1500 lo0: flags=8049 mtu 16384 inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3 inet6 ::1 prefixlen 128 inet 127.0.0.1 netmask 0xff000000