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Nexus 5596 (L3) ARP discard

Nexus 5596 (L·) running NX-OS 5.0(3)N2(1).

We are experiencing some issues about ARP dropped packets in one of the VLANs defined in the N5k.

When we displays ARP statistics, only 1% are been received, while in other environment the numbers are near 10%.

This is the output after clearing the stats:

ROISBDEV1CN# sh ip arp statistics

ARP packet statistics for context default


Total 17590, Requests 4275, Replies 13315, Requests on L2 0, Replies on L2 0,

Gratuitous 25, Dropped 0


Total 2603205, Requests 13315, Replies 4256, Requests on L2 0, Replies on L2 0

Proxy arp 0, Local-Proxy arp 0, Dropped 2585634

Received packet drops details:

    Appeared on a wrong interface       : 0

    Incorrect length                    : 0

    Invalid protocol packet             : 0

    Invalid context                     : 0

    Context not yet created             : 0

    Invalid layer 2 address length      : 0

    Invalid layer 3 address length      : 0

    Invalid source IP address           : 12

    Source IP address is our own        : 0

    No mem to create per intf structure : 0

    Source address mismatch with subnet : 0

    Directed broadcast source           : 0

    Invalid destination IP address      : 4

    Non-local destination IP address    : 2585618

    Invalid source MAC address          : 0

    Source MAC address is our own       : 0

    Received before arp initialization  : 0

    Received packet on unknown iod      : 0

    L2 packet on proxy-arp-enabled interface

                                        : 0

    L2 packet on untrusted L2 port      : 0

    Packet with VIP on standby FHRP     : 0

    Grat arp received on proxy-arp-enabled interface

                                        : 0

    Requests came for exising entries  

ARP adjacency statistics

Adds 35, Deletes 14, Timeouts 14

Cisco Employee

Nexus 5596 (L3) ARP discard


As we can see almost all drops are due to

Non-local destination IP address    : 2585618

'Non-local destination IP address' signifies that Nexus received an ARP

request/response with a different destination ip address than the

address configured on an interface on which the packet ingresses in.

So some stations in your network send a lot of ARPs for netwroks which does not exist on Nexus thus those are drops.

You can sniff for those ARPs to understand further who is creating it and fix.

You can use ethanalyzer for that. Using Ethanalyzer you can't capture the ARPs per VLAN. You can use arp

debug-filters to filter the arp packets that are received on the box.

Use "debug-filter ip arp interface "  with interface being

the svi-interface which belongs to the VLAN  for which you want the debugs.

It will be smth like

ethanalyzer local interface inband debug-filter ip arp interface


ethanalyzer local interface inband capture-filter "arp and net"  if you knows the network ARP is coming for.

Hope this helps.


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