MAC addresses, hostnames, and DHCP

[Travis Roy]

Sorry to top post, but..

Has anybody thought of the arp table?

Wouldn't that have to be updated when a different MAC address takes an IP.

I know when customers here need to make changes to equipment and bring 
up a new firewall with the same IP as the old one, one of us usually 
clears the arp cache on the router so the changes happen faster.

Perhaps our network is just setup whacky.. that wouldn't be a suprise :)

Ben Scott wrote:
> On 12/1/05, Paul Lussier <p.lussier at comcast.net> wrote:
> 
>>>So you can unplug from Ethernet and go Wireless and not loose your SSH
>>>connections (for one).
>>
>>It's not going to work that well ...
> 
> 
>   It should work *if* the SSH connection remains idle during the
> transition *and* the TCP sockets are not bound to a particular
> interface.  Since IP is stateless (remember *that* thread? ;-) ),
> higher layers shouldn't notice if an intermediate link goes away.
> 
>   However, there are some caveats.  If any traffic occurs (payload, or
> SSH control traffic like rekeying, keep-alive, etc.), TCP (or higher
> level protocols) may time out before the IP layer finishes coming back
> up.  This is especially likely if you're using SSH to tunnel X11.
> 
>   Likewise, if you bind ssh or sshd to a particular interface, when
> the interface goes down, the kernel is going to close the TCP socket,
> and your SSH session will disappear in a puff of data.
> 
> 
>>If you need state on the remote machine maintained, use screen or vnc.
> 
> 
>   That's certainly the "right" way to accomplish it.
> 
> -- Ben
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