大家好，我是讯享网，很高兴认识大家。

工作需求：通过mac地址查找PC3位于那个接入层交换机上

拓扑图如下：

讯享网

#在核心交换机上查找该mac地址对应的IP地址，属于那个VLAN，从哪个接口学习到的MAC地址信息。

<COREA>dis arp | include 5489-9810-380d

ARP Entry Types: D - Dynamic, S - Static, I - Interface, O - OpenFlow, RD - Redi

rect

EXP: Expire-time VLAN:VLAN or Bridge Domain

IP ADDRESS      MAC ADDRESS    EXP(M) TYPE/VLAN       INTERFACE        VPN-INSTA

NCE

--------------------------------------------------------------------------------

--------

192.168.100.100 5489-9810-380d   19   D/100           GE1/0/2         

--------------------------------------------------------------------------------

--------

Total:8         Dynamic:5       Static:0    Interface:3    OpenFlow:0

Redirect:0

（可选）继续通过命令display mac-address interface GE 1/0/2查找该MAC地址对应的端口号。发现380d是通过GE1/0/2口进来。

<COREA>display mac-address interface GE 1/0/2

Flags: * - Backup 

BD   : bridge-domain   Age : dynamic MAC learned time in seconds

-------------------------------------------------------------------------------

MAC Address    VLAN/VSI/BD   Learned-From        Type                Age

-------------------------------------------------------------------------------

5489-9810-380d 100/-/-       GE1/0/2             dynamic               -

5489-9810-380d 100/-/-       GE1/0/2             dynamic               -

-------------------------------------------------------------------------------

Total items: 2

核心交换机COREA上执行命令display mac-address，发现380d是通过GE1/0/2口进来。

[~COREA]dis mac-address

Flags: * - Backup 

BD   : bridge-domain   Age : dynamic MAC learned time in seconds

-------------------------------------------------------------------------------

MAC Address    VLAN/VSI/BD   Learned-From        Type                Age

-------------------------------------------------------------------------------

707b-e8a1-332c 10/-/-        Eth-Trunk1          dynamic               -

707b-e8a1-332c 20/-/-        Eth-Trunk1          dynamic               -

707b-e8a1-332c 100/-/-       Eth-Trunk1          dynamic               -

5489-9814-56ea 10/-/-        GE1/0/2             dynamic               -

5489-9810-380d 100/-/-       GE1/0/2             dynamic               -

707b-e8a1-332c 10/-/-        Eth-Trunk1          dynamic               -

707b-e8a1-332c 20/-/-        Eth-Trunk1          dynamic               -

707b-e8a1-332c 100/-/-       Eth-Trunk1          dynamic               -

5489-9814-56ea 10/-/-        GE1/0/2             dynamic               -

5489-9810-380d 100/-/-       GE1/0/2             dynamic               -

-------------------------------------------------------------------------------

Total items: 10

通过查看GE1/0/2口，发现这是一个下级联端口，此接口的描述提示连接到HUIJ01，然后到汇聚HUIJ01上继续排查。

<COREA>dis interface GE 1/0/2

GE1/0/2 current state : UP (ifindex: 7)

Line protocol current state : UP

Description: TO_HUIJ01

Switch Port, PVID :    1, TPID : 8100(Hex), The Maximum Frame Length is 9216

Internet protocol processing : disabled

IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 707b-e8ef-56b3

Last physical up time   : 2021-08-01 09:02:51

Last physical down time : 2021-08-01 09:02:31

Current system time: 2021-08-01 10:07:18

在汇聚交换机HUIJ01上执行命令 display mac-address

<HUIJ01>dis mac-address

MAC address table of slot 0:

-------------------------------------------------------------------------------

MAC Address    VLAN/       PEVLAN CEVLAN Port            Type      LSP/LSR-ID 

               VSI/SI                                              MAC-Tunnel 

-------------------------------------------------------------------------------

0000-5e00-010a 100         -      -      GE0/0/2         dynamic   0/-        

0000-5e00-010a 10          -      -      GE0/0/2         dynamic   0/-        

0000-5e00-0114 20          -      -      GE0/0/2         dynamic   0/-        

707b-e8ef-56b3 10          -      -      GE0/0/2         dynamic   0/-        

707b-e8ef-56b3 20          -      -      GE0/0/2         dynamic   0/-        

707b-e8ef-56b3 100         -      -      GE0/0/2         dynamic   0/-        

5489-9810-380d 100         -      -     GE0/0/4         dynamic   0/-        

5489-9814-56ea 10          -      -     GE0/0/1         dynamic   0/-        

-------------------------------------------------------------------------------

Total matching items on slot 0 displayed = 8

在汇聚交换机上查到380d是连接在当前交换机的GE0/0/4口上，属于VLAN100，此接口是与SW1交换机连接的中继端口。现在大致知道终端是连到那个接入层交换机，即SW1接入层交换机。

现在到SW1交换机上继续排查，发现终端是连接到GE0/0/1端口上。这样最终就能定位到了是那台主机连接到这个端口。

[SW1]dis mac-address

MAC address table of slot 0:

-------------------------------------------------------------------------------

MAC Address    VLAN/       PEVLAN CEVLAN Port            Type      LSP/LSR-ID 

               VSI/SI                                              MAC-Tunnel 

-------------------------------------------------------------------------------

0000-5e00-010a 100         -      -      GE0/0/4         dynamic   0/-        

5489-9810-380d 100         -      -      GE0/0/1         dynamic   0/-        

707b-e8ef-56b3 100         -      -      GE0/0/4         dynamic   0/-        

-------------------------------------------------------------------------------

Total matching items on slot 0 displayed = 3