Use IP addresses to quickly locate switch ports and target hosts

Note: As a manager, quickly locate the switch port, to find out the IP and Mac correspondence is a skill that must be mastered, familiar with the above methods can be used for troubleshooting to achieve a multiplier effect.

The best way to hunt down an IP address is to find out where the IP address is physically connected to the network. To do this, connect the machine to the port of the switch to match the MAC address of the machine. First ping the IP address, and then get the MAC address of the machine from the ARP table.

1. Locate mac--We use the ping command to see how much of the MAC address of his machine card.

interface:192.168.3.41 on Interface 0x1000003

Internet Address Physical Address Type

192.168.1.1 00-30-AB-04-26-DD Dynamic
192.168.1.11 00-0d-56-21-af-d6 Dynamic

From the local ARP cache to see this suspicious IP address of the MAC address is 00-0d-56-21-af-d6, log on the switch to see sure enough or this address.

Bj-sw#show ARP | In 192.168.1.11

Internet 192.168.1.11 3 000d.5621.afd6 ARPA Vlan20

2. Locating the connected switch Port-Next, we need to know which switching machine his machine is receiving.

Bj-sw#show mac-address-table Dynamic Address 000d.5621.afd6

Unicast Entries

VLAN MAC address type protocols port

-------+---------------+--------+---------------------+--------------------

000D.5621.AFD6 Dynamic IP,IPX GIGABITETHERNET3/2

From the result it is connected via a gigabit port. Let's look at the neighbor (this is the two cascade switch of the core switching machine)

Bj-sw-419-1-4#sh CDP Neighbors

Capability codes:r-Router, T-trans Bridge, B-source Route Bridge

S-switch, H-host, I-igmp, R-repeater, P-phone

Device ID Local intrfce holdtme Capability Platform Port ID

Sw-419-2-3 GIG3/4 SI ws-c3550-4gig 0/2
Sw-419-1-3 GIG3/3 168 SI ws-c3550-4gig 0/2
Sw-440-1-4 GIG3/1 173 SI ws-c3550-4gig 0/2
Sw-440-2-4 GIG3/2 143 SI ws-c3550-2gig 0/2

Finally found it, in Sw-440-2-4 GIG3/2 143 SI ws-c3550-2gig 0/2, below we directly log into the sw-440-2-4 This switch, enter the Mac lookup.

Sw-440-2-4#show mac-address-table Dynamic Address 000d.5621.afd6

Mac Address Table

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

Vlan Mac Address Type Ports

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

000d.5621.afd6 DYNAMIC FA0/23

Total Mac Addresses for this criterion:1

3. Positioning and setting--then directly to this machine according to the jumper table of the integrated cabling, then close the port.

Use IP addresses to quickly locate switch ports and target hosts