C3750 strange arp reply situation

[mihaitanasescu]

Hello,

I've just recently acquired a cisco 3750 switch and after configuring I noticed the following problem:

(The current setup is: cisco3750 - 48 ports/ 24 ports used each in its own vlan and with its own ip address / a trunk port)

If I arping from a linux host the IP that corresponds to the Vlan I'm currently plugged in, for each arp request I get back 2 arp replies.

I have proxy arp disabled for every port.

I have made the tests without any other hosts connected.

Is this an IOS bug ?

[mchin345]

not sure of the issue, but you can prevent malicious attacks on the switch by not relaying invalid ARP requests and responses to other ports in the same VLAN by using Dynamic ARP Inspection, refer to the following link for more information :

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_guide_chapter09186a00802126b8.html