How to find the host based on IP address

Unanswered Question
Oct 13th, 2008

Hi,

i have host connected to port on my swtiched network, please let me know on which and which post the host is connected

Host ip:10.1.89.50

1 step:

core720#p 10.1.89.50(host IP)

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.89.50, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

core720#

step 2:

core720#sh arp | in 89.50

Internet 10.1.89.50 0 0050.564b.65b6 ARPA Vlan90

step 3:

core720#sh mac-ad

core720#sh mac-address-table | in 0050.564b.00b6

* 90 0050.564b.65b6 dynamic Yes 0 Po10

core720#

please guide me from here to locate the on which switch the host(10.1.89.50) is connected

I have this problem too.
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Jon Marshall Mon, 10/13/2008 - 08:41

You need to log onto the switch at the other end of po10 which is port-channel10.

1) sh etherchannel summary

will show you the individual ports within an etehrchannel. So lets assume po10 is made up of 4 ports gi3/1, 2, gi4/1, 2.

Pick one and then

2) sh cdp neigh gi3/1 det

this should give you the attached switch IP address - assuming it is a managed switch. Log onto that switch and repeat your step 3 ie.

sh mac-address-table address 0050.564b.00b6

Jon

Collin Clark Mon, 10/13/2008 - 08:43

You're on the right track. The switch has learned the MAC from Po10. Where does that go? An easy way to find out is 'show cdp nei inter [port channel member]'. That will show you the device. Then go to that device and show the MAC and keep going to the switch until you find the port.

http://www.packetpros.com/wiki/index.php/Cisco and go to How do I find a device in my network?

Hope that helps.

UCBNOCWAN Mon, 10/13/2008 - 09:12

Dear All,

still i am unable to locate plz find the output

core720#sh etherchannel su

1 Po1(SU) - Gi1/1(P) Gi1/2(P) Gi6/1(P) Gi6/2(P)

10 Po10(SU) - Gi1/21(P) Gi1/22(D)

11 Po11(SU) - Gi1/23(P) Gi1/24(D)

21 Po21(SU) - Gi8/1(P) Gi8/2(P)

50 Po50(SU) - Gi1/5(P) Gi1/6(P)

51 Po51(SU) - Gi1/7(P) Gi1/8(P)

52 Po52(SU) - Gi1/9(P) Gi1/10(P)

53 Po53(SU) - Gi1/11(P) Gi1/12(P)

core720#

core720#sh cdp ne gi1/21 de

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

Device ID: 3750-VC-2

Entry address(es):

IP address: 10.1.128.101

3750-VC-2#sh mac-address-table | in 0050.564b.65b6

90 0050.564b.65b6 DYNAMIC Po41

3750-VC-2#sh eth

3750-VC-2#sh etherchannel su

w - waiting to be aggregated

d - default port

Group Port-channel Protocol Ports

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

10 Po10(SU) - Gi1/0/49(P) Gi1/0/50(D)

11 Po11(SD) - Gi1/0/51(D) Gi1/0/52(D)

31 Po31(SU) LACP Gi1/0/1(P) Gi1/0/2(P) Gi1/0/3(P)

32 Po32(SU) LACP Gi1/0/5(P) Gi1/0/6(P) Gi1/0/7(P)

41 Po41(SU) LACP Gi1/0/41(P) Gi1/0/42(P) Gi1/0/43(P)

42 Po42(SU) LACP Gi1/0/33(P) Gi1/0/34(P) Gi1/0/35(P)

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

3750-VC-2#sh mac-address-table | in 0050.564b.65b6

90 0050.564b.65b6 DYNAMIC Po41

3750-VC-2#sh eth

BRA-R8-3750-VC-2#sh etherchannel su

Flags: D - down P - in port-channel

I - stand-alone s - suspended

H - Hot-standby (LACP only)

R - Layer3 S - Layer2

U - in use f - failed to allocate aggregator

u - unsuitable for bundling

w - waiting to be aggregated

d - default port

Number of channel-groups in use: 6

Number of aggregators: 6

Group Port-channel Protocol Ports

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

10 Po10(SU) - Gi1/0/49(P) Gi1/0/50(D)

11 Po11(SD) - Gi1/0/51(D) Gi1/0/52(D)

31 Po31(SU) LACP Gi1/0/1(P) Gi1/0/2(P) Gi1/0/3(P)

32 Po32(SU) LACP Gi1/0/5(P) Gi1/0/6(P) Gi1/0/7(P)

41 Po41(SU) LACP Gi1/0/41(P) Gi1/0/42(P) Gi1/0/43(P)

42 Po42(SU) LACP Gi1/0/33(P) Gi1/0/34(P) Gi1/0/35(P)

3750-VC-2#sh cdp ne gi1/0/41 de

3750-VC-2#sh cdp ne gi1/0/42 de

3750-VC-2#sh cdp ne gi1/0/43 de

3750-VC-2#

Collin Clark Mon, 10/13/2008 - 09:21

If the switches are connected to non-Cisco or blade server switches (or even a server), you may hit this dead end and you have to physically trace one of the cables to see where it goes. Also double check that CDP is running on those ports.

UCBNOCWAN Mon, 10/13/2008 - 09:34

Hi ALl

CDP is enabled

GigabitEthernet1/0/41 is up, line protocol is up

Encapsulation ARPA

Sending CDP packets every 60 seconds

Holdtime is 180 seconds

GigabitEthernet1/0/42 is up, line protocol is up

Encapsulation ARPA

Sending CDP packets every 60 seconds

Holdtime is 180 seconds

GigabitEthernet1/0/43 is up, line protocol is up

Encapsulation ARPA

Sending CDP packets every 60 seconds

Holdtime is 180 seconds

plz advice

Jon Marshall Mon, 10/13/2008 - 09:37

Yes but CDP would need to be advertised from the device at the other end as well and it doesn't appear to be.

It looks like you have VMWare servers at the end of this link.

Jon

Collin Clark Mon, 10/13/2008 - 09:40

OK, then you know what ports the uplink to the blade center switch is. From there you would have to do a physical trace (or buy Cisco blade switches).

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