How to know which interfaces are going to which switch?

[chandra_rc16]

How to know which interfaces are going to which switch ?

I know that cdp will show this information. But CDP will not show info about the devices connected to my device and whose link between is administratively down.

Regards,

Chandu

[cadet alain]

Hi,

You want to know  end devices location ? in that case you could use L2  traceroute on the switch:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_55_se/commmand/reference/cli3.html#wp1944445

Regards

Alain

Don't forget to rate helpful posts.

[chandra_rc16]

I don't want to the end devices location.

For example, i have a switch that connect to multiple switches few using etherchannels and few using stand-along ports.

So assume that one of the link whether it may be entire port-channel or a stand alone link that connects to another switch has been shut down manually by some x person...

Then how can i know that which interfaces are connecting to that switch. In this case i think CDP will not  help because it will hold the information of ports that are up.

Regards,
Chandu

[Jan Rolny]

Hi,

you can simply use SNMP and track/monitor interested ports if they are shut down or not. Also you can monitor who logged in so you will know who made this changes on what switch.

Regards,

Jan

[chandra_rc16]

Jan, actually i just want to know which interfaces were used to connect to the other device even when the links between them are down.

I can see this by manually entering into the datacentre and go through the physical connections. But is it possible to see through ios ?

Regards,
Chandu

[Jan Rolny]

Hi Chandu,

now I see what you actually need :-)

From my point of view it is not possible. When link is down and you have not any log where you can see some operations few days back so it is not possible(of course if your log buffer is not larger to see logs localy).

So you think somebody connected to your switch(unauthorized access). Other things to prevent this access is configure port security or shutdown unused port permanently.

Regards,

Jan

[chandra_rc16]

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From my point of view it is not possible.

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Do you mean we cannot know through which interfaces the other end was connected, right ?

Regards,
Chandu

[Ankur Arora · Accepted solution]

Chandu,

When the interface is shut, theres no way you can check that as there will no data packet passing through that link.

You can only find that info from the previous logs of the switch, but i don't think there is any feature which can tell you the other end info when link is shut.

I mean take it this way, you are at one end of a road and its blocked in front of you, how will you know whats on the other end untill you contact someone on the other side.

Thanks

Ankur

[Jan Rolny · Accepted solution]

Yes, in case you don't have any log where you can look on or you don't have any monitoring system so it is not possible. which interface wa up e.g. 2 days ago.

Only thing what crossed my mind would be chceck counters all interfaces which are down. In case interface were not used any time so only one interface will have some packet count when you issue sh inetrface interface number

Regards,

Jan