SNMP clients connected to a switch

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Task; To identify what is connected to each port of a Summit 48si switch (using snmp)
The devices are configured with snmpv3.

Im using snmpwalk on a linux box to query the switch.

Is it possible through snmp to query the port of the switch, and determine the machine connected to it?.


If so, what OID should I be using?

Thanks
Liam
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Liam O Donnell

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Posted 3 years ago

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Stephen Williams, Employee

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You can try to start a SNMP walk at .1.3.6.1.4.1.1916.1.16.1 or .1.3.6.1.2.1.4.22 to see what you can find.
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Stephen Williams, Employee

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Also use a MIB browser UI.  It makes life much easier to find the right MIB.  Then you can use the CLI.
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Ronald Dvorak, Embassador

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You'd use...

- dot1dTpFdbAddress = MAC
- dot1dTpFdbPort = port

If you combine them you'd get MAC/port - here a example with a Fleview in Netsight...

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Liam O Donnell

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Thanks you for your response.

The latter produced data on the other switches in the network, I was able to locate the Mac address of the device attached to the switch with the first OID. However, I could not see hbow I could use this to locate the port it is connected to on the switch ...

SNMPv2-SMI::enterprises.1916.1.16.1.1.3.22015.325184 = Hex-STRING: F8 B1 56 A4 F9 37

How do I identify which port on the switch this device is connected?

The port list of the switch are shown below;

ifDescr.1
Summit48si-Port 1
ifDescr.2
Summit48si-Port 2
ifDescr.3
Summit48si-Port 3
ifDescr.4
Summit48si-Port 4
ifDescr.5
Summit48si-Port 5
ifDescr.6
Summit48si-Port 6
ifDescr.7
Summit48si-Port 7
ifDescr.8
Summit48si-Port 8
ifDescr.9
Summit48si-Port 9
ifDescr.10
Summit48si-Port 10
ifDescr.11
Summit48si-Port 11
ifDescr.12
Summit48si-Port 12
ifDescr.13
Summit48si-Port 13
ifDescr.14
Summit48si-Port 14
ifDescr.15
Summit48si-Port 15
ifDescr.16
Summit48si-Port 16
ifDescr.17
Summit48si-Port 17
ifDescr.18
Summit48si-Port 18
ifDescr.19
Summit48si-Port 19
ifDescr.20
Summit48si-Port 20
ifDescr.21
Summit48si-Port 21
ifDescr.22
Summit48si-Port 22
ifDescr.23
Summit48si-Port 23
ifDescr.24
Summit48si-Port 24
ifDescr.25
Summit48si-Port 25
ifDescr.26
Summit48si-Port 26
ifDescr.27
Summit48si-Port 27
ifDescr.28
Summit48si-Port 28
ifDescr.29
Summit48si-Port 29
ifDescr.30
Summit48si-Port 30
ifDescr.31
Summit48si-Port 31
ifDescr.32
Summit48si-Port 32
ifDescr.33
Summit48si-Port 33
ifDescr.34
Summit48si-Port 34
ifDescr.35
Summit48si-Port 35
ifDescr.36
Summit48si-Port 36
ifDescr.37
Summit48si-Port 37
ifDescr.38
Summit48si-Port 38
ifDescr.39
Summit48si-Port 39
ifDescr.40
Summit48si-Port 40
ifDescr.41
Summit48si-Port 41
ifDescr.42
Summit48si-Port 42
ifDescr.43
Summit48si-Port 43
ifDescr.44
Summit48si-Port 44
ifDescr.45
Summit48si-Port 45
ifDescr.46
Summit48si-Port 46
ifDescr.47
Summit48si-Port 47
ifDescr.48
Summit48si-Port 48
ifDescr.49
Summit48si-Port 49
ifDescr.50
Summit48si-Port 50
ifDescr.22001
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Liam O Donnell

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I Tried your suggesteion Ronald, but 'No data available in this subtree' was returned.

The test switch is a Summit 48si. I have Dell PCs attached as podia in lecture theatres back to this switch.
It would be very useful to be able to dynamically identify the switch and port a specific PC is connected to.

Thanks
Liam
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Drew C., Community Manager

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I think the best you'll be able to do in this case is to retrieve the MAC address or IP address of devices connected to a specific port.
Querying the individual device itself would yield you more information if SNMP is enabled, which isn't commonly enabled by default on most PCs.
As Stephen suggested above, it's easiest to open the MIB in a tool such as Netsight or iReasoning to determine which OIDs to poll.
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Liam O Donnell

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We used to have a simple tool for identifying the device attached to a port, or to search all the switches for a specific device (usually by mac address).

Problem 1.
-------------
I made some headyway talking to the 48si's, using
1.3.6.1.4.1916.1.16.1.1.3/4/5
1.3.6.1.4.1916.1.16.1.1.3.22009.17280 -> (mac address)
1.3.6.1.4.1916.1.16.1.1.4.22009.17280 -> (looks like the port number)
The 22009 is ifVlan definition, which can be different between the switches.


however, when I scan all the switches, I get more than one switch responding.

The last number is always the same between the switches, I have been unable to determine from snmp which switch the PC is actually connected to. Any ideas?


Problem 2.
-------------
One third of our switches are Extreme X440-48t switches. I have been unable to locate similar data from these switches ... Do you knmow what oid(s) I should be  looking at.


Thanks
Liam

PS: I am using a MibBrowser from ManageEngine.
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Liam O Donnell

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I found an entry which is not in the mib that I have. (Dated January 2015)
1.3.6.1.4.1.1916.1.16.4
I have ..16.3 and 16.5 but not ...16.4
Where can I get the latest mib which hopefully will have this info.?

Thanks
Liam
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Drew C., Community Manager

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Hi Liam,
This article will tell you how to find the latest MIB files for EXOS and ExtremeWare:
https://gtacknowledge.extremenetworks.com/articles/Q_A/Location-of-Extreme-Network-MIBs-Management-I...

If I use the "Table View" feature in the iReasoning MIB Browser, the extremeFdbMacExosFdbTable contains most of the information available about a particular port's connection.
That begins at OID  .1.3.6.1.4.1.1916.1.16.4 (which you've mentioned above).  This is for EXOS, I'm not sure about ExtremeWare (for the 48si).