{"id":1380,"date":"2012-11-11T13:59:43","date_gmt":"2012-11-11T18:59:43","guid":{"rendered":"http:\/\/www.microdevsys.com\/WordPress\/?p=1380"},"modified":"2012-11-11T14:06:35","modified_gmt":"2012-11-11T19:06:35","slug":"how-to-find-the-mac-address-of-an-ethernet-or-wireless-card","status":"publish","type":"post","link":"https:\/\/microdevsys.com\/wp\/how-to-find-the-mac-address-of-an-ethernet-or-wireless-card\/","title":{"rendered":"How to find the MAC address of an ethernet or wireless card."},"content":{"rendered":"

To find the MAC address of an ethernet or wireless card is generally straight forward for straight forward configurations.  The MAC address is a unique identifier for every NIC (Network Interface Card) that uniquely identifies that card amongst all others.<\/p>\n

There's several commands that can be used for this depending on your network configuration and setup.  The basic command to use for this is ifconfig <\/strong>(Equivalent of netstat -ie<\/strong>):<\/p>\n

# ifconfig eth0
\n\teth0      Link encap:Ethernet  HWaddr 1C:6F:65:3F:FC:14<\/strong><\/span> 
\n\t          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
\n\t          RX packets:339061 errors:0 dropped:0 overruns:0 frame:0
\n\t          TX packets:183764 errors:0 dropped:0 overruns:0 carrier:0
\n\t          collisions:0 txqueuelen:1000
\n\t          RX bytes:82692563 (78.8 MiB)  TX bytes:121295829 (115.6 MiB)
\n\t          Interrupt:32 Base address:0x4000 <\/p>\n

\t<\/span><\/p>\n

However once the network configuration becomes a bit more complex, this just won't do:<\/p>\n

For example, in a bonding configuration, ifconfig<\/strong> will list the same MAC address for all the cards:<\/p>\n

# ifconfig<\/strong><\/span><\/p>\n

bond0     Link encap:Ethernet  HWaddr 1C:6F:65:3F:FC:14 
\n\t          inet addr:192.168.7.10  Bcast:192.168.1.255  Mask:255.255.254.0
\n\t          inet6 addr: fe80::1e6f:65ff:fe3f:fc14\/64 Scope:Link
\n\t          UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1
\n\t          RX packets:345632 errors:0 dropped:0 overruns:0 frame:0
\n\t          TX packets:186780 errors:0 dropped:0 overruns:0 carrier:0
\n\t          collisions:0 txqueuelen:0
\n\t          RX bytes:85617681 (81.6 MiB)  TX bytes:122381805 (116.7 MiB)
\n\t<\/span><\/p>\n

eth0      Link encap:Ethernet  HWaddr 1C:6F:65:3F:FC:14 
\n\t          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
\n\t          RX packets:345632 errors:0 dropped:0 overruns:0 frame:0
\n\t          TX packets:186780 errors:0 dropped:0 overruns:0 carrier:0
\n\t          collisions:0 txqueuelen:1000
\n\t          RX bytes:85617681 (81.6 MiB)  TX bytes:122381805 (116.7 MiB)
\n\t          Interrupt:32 Base address:0x4000 <\/span><\/p>\n

eth1      Link encap:Ethernet  HWaddr 1C:6F:65:3F:FC:14 
\n\t          UP BROADCAST SLAVE MULTICAST  MTU:1500  Metric:1
\n\t          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
\n\t          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
\n\t          collisions:0 txqueuelen:1000
\n\t          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)<\/p>\n

\t<\/span><\/p>\n

Unfortunately, even with udevadm the addresses come back looking the same:<\/p>\n

# udevadm info -a -p \/sys\/class\/net\/eth0|grep address<\/strong>
\n\t    ATTR{address}=="1c:6f:65:3f:fc:14"
\n\t# udevadm info -a -p \/sys\/class\/net\/eth1|grep address<\/strong>
\n\t    ATTR{address}=="1c:6f:65:3f:fc:14"
\n\t# udevadm info -a -p \/sys\/class\/net\/wlan0|grep address<\/strong>
\n\t    ATTR{address}=="00:25:86:f1:65:d0"
\n\t# udevadm info -a -p \/sys\/class\/net\/bond0|grep address<\/strong>
\n\t    ATTR{address}=="1c:6f:65:3f:fc:14"
\n\t<\/span><\/p>\n

An alternate command is:<\/p>\n

# udevadm info –attribute-walk –path \/sys\/class\/net\/eth0
\n\t<\/span><\/strong><\/p>\n

And after a bonding configuration, wlan0<\/strong> will show the MAC of bond0<\/strong>.  In cases like this, we can use the bond0<\/strong> interface to get the real MAC<\/strong> address for the device:<\/p>\n

# cat \/proc\/net\/bonding\/bond0<\/strong>
\n\tEthernet Channel Bonding Driver: v3.6.0 (September 26, 2009)<\/span><\/p>\n

Bonding Mode: load balancing (round-robin)
\n\tMII Status: up
\n\tMII Polling Interval (ms): 100
\n\tUp Delay (ms): 0
\n\tDown Delay (ms): 0<\/span><\/p>\n

Slave Interface: eth0<\/strong>
\n\tMII Status: up
\n\tSpeed: 1000 Mbps
\n\tDuplex: full
\n\tLink Failure Count: 0
\n\tPermanent HW addr: 1c:6f:65:3f:fc:14<\/strong><\/span>
\n\tSlave queue ID: 0<\/span><\/p>\n

Slave Interface: eth1<\/strong>
\n\tMII Status: down
\n\tSpeed: Unknown
\n\tDuplex: Unknown
\n\tLink Failure Count: 0
\n\tPermanent HW addr: 90:e2:ba:1a:08:28<\/strong><\/span>
\n\tSlave queue ID: 0
\n\t#
\n\t<\/span><\/p>\n

Any active devices in a bonding configuration will show the MAC of the primary device but using the above command will display the real \/ permanent MAC address of the participating NIC's.<\/p>\n

Cheers,
\n\tTK
\n\t<\/span><\/p>\n\n

\n\n\t\t\n
    \n\t\t\t <\/ul>\n <\/div> \n","protected":false},"excerpt":{"rendered":"

    To find the MAC address of an ethernet or wireless card is generally straight forward for straight forward configurations.  The MAC address is a unique identifier for every NIC (Network Interface Card) that uniquely identifies that card amongst all others. There's several commands that can be used for this depending on your network configuration and […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"footnotes":""},"categories":[3],"tags":[330,1417,1418,1416,534,437,340,734],"class_list":["post-1380","post","type-post","status-publish","format-standard","hentry","category-unix-linux-admin-stuff","tag-address","tag-cardk","tag-discover","tag-ethernet-or-wireless","tag-find","tag-how","tag-mac","tag-nic"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/posts\/1380","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/comments?post=1380"}],"version-history":[{"count":0,"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/posts\/1380\/revisions"}],"wp:attachment":[{"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/media?parent=1380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/categories?post=1380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/microdevsys.com\/wp\/wp-json\/wp\/v2\/tags?post=1380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}