【记录】如何永久修改网卡mac地址（重启重装都不会改变）

第一步：确定网卡硬件的magic值

[root@Zabbix-yuanzhan ~]# ip a
2: em1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether f0:4d:a2:73:9a:9a brd ff:ff:ff:ff:ff:ff
    inet 156.236.93.10/25 brd 156.236.93.127 scope global em1
    inet6 fe80::f24d:a2ff:fe73:9a9a/64 scope link 
       valid_lft forever preferred_lft forever
3: em2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether f0:4d:a2:73:9a:9b brd ff:ff:ff:ff:ff:ff

[root@Zabbix-yuanzhan ~]# lspci | grep Eth
02:00.0 Ethernet controller: Intel Corporation I350 Gigabit Network Connection (rev 01)
02:00.3 Ethernet controller: Intel Corporation I350 Gigabit Network Connection (rev 01)

[root@Zabbix-yuanzhan ~]# lspci -nn | grep Eth
02:00.0 Ethernet controller [0200]: Intel Corporation I350 Gigabit Network Connection [8086:1521] (rev 01)
02:00.3 Ethernet controller [0200]: Intel Corporation I350 Gigabit Network Connection [8086:1521] (rev 01)
    解释：上面 [8086:1521] 中 1521为VenID，8086为DevID，magic的值为：0x15218086

#或者这样看，根据硬件地址来查询magic值
    [root@Zabbix-yuanzhan ~]# lspci -s 02:00.3 -nn
    02:00.3 Ethernet controller [0200]: Intel Corporation I350 Gigabit Network Connection [8086:1521] (rev 01)

#或者观察eeprom 0×0010地址处的值获得，这样直接调取0x0010的值，可以从结果中看出，magic的值和我们手工获取的一致
    [root@Zabbix-yuanzhan ~]# ethtool -e em2 | grep 0x0010 | awk '{print "0x"$13$12$15$14}'
    0x15218086

第二：根据网卡当前的mac确定，其在ethtool中的存储位置

[root@Zabbix-yuanzhan ~]# ip a
2: em1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether f0:4d:a2:73:9a:9a brd ff:ff:ff:ff:ff:ff
    inet 156.236.93.10/25 brd 156.236.93.127 scope global em1
    inet6 fe80::f24d:a2ff:fe73:9a9a/64 scope link 
       valid_lft forever preferred_lft forever
3: em2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether f0:4d:a2:73:9a:9b brd ff:ff:ff:ff:ff:ff

[root@Zabbix-yuanzhan ~]# ethtool -e em2 | grep "9a 9b"
0x0000:     f0 4d a2 73 9a 9b 00 08 ff ff 57 10 ff ff ff ff
解释：根据过滤知道这一行确实是我们上面看到的mac地址行，但只有前面6个才是mac地址，后面的不用理会
其中：f0 的定位是 0x0000 ; 4d的定位是 0x0001；以此类推

第三：修改mac地址,我们把 f0:4d:a2:73:9a:9b 改成f0:4d:a2:73:9a:9c

#语法格式：ethtool -E eth0 magic [magic地址] offset [定位值]
    ethtool -E em2 magic 0x15218086 offset 0x0000 value 0xf0
    ethtool -E em2 magic 0x15218086 offset 0x0001 value 0x4d
    ethtool -E em2 magic 0x15218086 offset 0x0002 value 0xa2
    ethtool -E em2 magic 0x15218086 offset 0x0003 value 0x73
    ethtool -E em2 magic 0x15218086 offset 0x0004 value 0x9a
    ethtool -E em2 magic 0x15218086 offset 0x0005 value 0x9c

第四：重启验证

[root@Zabbix-yuanzhan ~]# ip a
2: em1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether f0:4d:a2:73:9a:9a brd ff:ff:ff:ff:ff:ff
    inet 156.236.93.10/25 brd 156.236.93.127 scope global em1
    inet6 fe80::f24d:a2ff:fe73:9a9a/64 scope link 
       valid_lft forever preferred_lft forever
3: em2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether f0:4d:a2:73:9a:9c brd ff:ff:ff:ff:ff:ff

附：另一种修改mac的工具：macchanger 请自行测试