[c-nsp] same mac for different ip addr

[Brandon Ewing]

On Tue, Apr 20, 2010 at 08:35:48AM +0200, Arne Larsen / Region Nordjylland wrote:
> Hi all.
> 
> Can someone give me an answer on this.
> We have a platform that run on Redhat EntR5.3 and uses subinterfaces.
> I seem that the platform sends the same MAC for all interfaces. 
> What happens in the arp table on the default gateway. Does it keep track of all ip address or does it overwrite it.  /Arne

When you say subinterfaces -- do you mean vLAN/dot11q interfaces configured
with vconfig, or secondary addresses configured as aliases?

In either case, it isn't a major issue.  If it's vLANs, most switches
maintain a different layer 2 forwarding database for each vLAN, so the same
MAC in multiple vLANs is handled appropriately.  If it's aliases, it still
isn't an issue, as the layer 3 device will gladly store the same MAC address
in the ARP table for multiple IPs.

-- 
Brandon Ewing                                        (nicotine at warningg.com)
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