Re: [vserver] ping vs. IP address vs. MAC (address)

From: Dennis Roos <dennis.roos_at_gmail.com>
Date: Fri 01 May 2009 - 22:02:21 BST
Message-ID: <49FB635D.4090908@gmail.com>

What you could do is clear the arp entry for the address on your
router/switch and generate some traffic (eg. ping) on the interface.
Mostly it takes 5 minutes for a router to learn about the new address,
as it caches the information for that amount of time.

Best regards,
Dennis Roos

Roderick A. Anderson wrote:
> I'm asking for a clue stick here. First time I've run into this issue
> ... hard. Be a few times where it took a bit for outbound traffic to
> get a route but can't remember running into this problem.
>
> The short question is: does the network/NIC _know_ which IP address it
> is responding for when a ping request comes in or does it just respond
> to the ping request at the MAC (hardware?) level?
>
> I have two hosts and each of their guests has its own IP address. I am
> trying to move the guest's services from one host to the other. The
> new and old guests both use the same IP address. So I shut down the
> old guest and then start up the new guest on the other system.
> Network traffic to the new guest, except pings, doesn't work.
> Iptables, ip addr ls, ifconfig, etc., all appear to be good.
>
> I'm guessing the routing is sending the ping request to the old
> guest's MAC.
>
> Thoughts, Ideas?
>
> \\||/
> Rod
Received on Fri May 1 22:04:40 2009

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