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Author Topic: Problem discovering a node with 2 MAC addresses on a single NIC  (Read 124 times)

Slinger

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Problem discovering a node with 2 MAC addresses on a single NIC
« on: October 23, 2017, 10:41:35 PM »
I have a Dell PowerEdge R710 connected to a Dell N3024 switch.  The R710 has an iDRAC6 Express (remote access controller) with its own MAC address that shares the physical NIC with the computer, so there are two MAC addresses on that one NIC.  When I run a discover on the switch, Nedi sees both MAC addresses in the BridgeFwd (SNMP) part, but tosses the one used by the operating system and keeps the one for the iDRAC.

This is the order that is shown during the discover:

- main MAC on edge port 15
- main MAC on uplink port 24
- iDRAC MAC on uplink port 24
- iDRAC MAC on edge port 15

When I do Nodes->Status in the GUI with the iDRAC MAC, it is shown as a node on port 15.  However, the MAC that is used by the operating system just shows "No Node".  The other nodes connected to this switch show up as expected.

Any ideas on how to correct this?

rickli

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Re: Problem discovering a node with 2 MAC addresses on a single NIC
« Reply #1 on: October 24, 2017, 11:58:31 AM »
Is it possible that iDRAC got discovered as non-snmp device? In that case, the concerning switch port is treated as link (not keeping any client MAC addresses).

You can add a border in nedi.conf matching the iDRAC's names and delete them from the devices to fix this.
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Slinger

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Re: Problem discovering a node with 2 MAC addresses on a single NIC
« Reply #2 on: October 24, 2017, 07:48:18 PM »
The iDRAC is discovered as a node, not a device.  I've also duplicated the problem with a different computer that doesn't have an iDRAC, so that's not the cause.  After a little more digging, I believe it may be happening because the MAC address appears in 2 VLANs on the same switch, and one overwrites the other in the database.  I looked into using the "useivl" option, but the switch doesn't appear to have vlanid in a table that I can get to with snmp.  I might be able to do it with a command line, though.

rickli

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Re: Problem discovering a node with 2 MAC addresses on a single NIC
« Reply #3 on: October 25, 2017, 10:20:23 AM »
You wrote earlier it has its own MAC address. In that case you should see both attached to the same port. If the switch supports the Q-Bridge MIB, even the Vlans should be correct. IVL can be enabled to keep same MAC addresses in different Vlans, otherwise they'd be overwriting themselves...

I don't quite understand why you won't see both MACs on that port. nedi.pl -vdb might show you what's going on...
Please consider Other-Invoices on your NeDi installation for an annual contribution, tx!
-Remo