em(4) device still 'freezes' on latset CVSup'd 6.x ...

Antony Mawer fbsd-stable at mawer.org
Thu May 4 13:07:04 UTC 2006

On 4/05/2006 6:20 PM, Rutger Bevaart wrote:
> Technically it's not routes that are not being updated, but a stale 
> (outdated) ARP cache on the other hosts. The system with the new 
> alias'ed IP needs to do a gratuitous ARP (broadcast ARP for it's own 
> IP). As an intermediate solution you could flush the ARP cache on the 
> hosts with stale cache (usually a router or L3 switch on the subnet). 
> Sounds like a bug in the em driver. Anybody do sniffing to see if it 
> does send out ARPs? If not I can test on one of our Dell 2850's with em's.

If true, this would explain something I've seen this a couple of times 
when an IP address has changed, and the ARP cache on the router had to 
be flushed before the new address was picked up correctly. In all cases 
this was running on machines with em0 (Intel Pro/1000) NICs.

I hadn't thought too much of it at the time as it was not a frequent 
occurrence and thus I put it down to one of those things that "just 


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