Need help configuring my network

Eric "Shubes" plug at shubes.net
Thu May 4 10:05:09 MST 2006


Darrin Chandler wrote:
> On Wed, May 03, 2006 at 10:20:51PM -0700, Dazed_75 wrote:

> Hmm. Does the router doing dhcp support RIP? Some do, some don't.

Can you explain what RIP is/does?

>> BTW, a reminder that both interfaces get the same DNS IPs from the one
>> router acting as a DHCP server.  So the issue may be with the dhclient
>> effects but somehow the effect seems to change which interface traffic
>> is going to.
> 
> The dhcp client (dhclient) gets its info and sets up the ip address,
> subnet, and *routing*. Normally you only do this on one interface, and
> it's your only link, and it works great. Add a second interface and one
> of the dhclients stomps on the routing of the other. Both dhclients
> remain active and periodically check in with the dhcp server, and will
> renew their info, including *routing*. So, with multiple dhcp interfaces
> it's anyone's guess how things will route at any particular moment.

That's a very good description of what's going on here. Thanks, Darrin. 
I have two interfaces on my notebook, and have been meaning to do a bit 
of testing, which I've now done. I have an IPCop box and a wireless 
router configured on a *different subnet*. Whichever interface is 
brought up last 'wins' the routing war (is used as the external 
gateway). If the interface which came up last is brought down, network 
access is lost, because the gateway route is removed. If the interface 
which came up first is brought down, network access persists. I'm 
guessing that as DHCP leases are renewed, the connection(s) would remain 
working, and the most recently renewed lease would become the default route.

I'm wondering why anyone would want more than one network interface on 
the same subnet active at the same. I can't think of any reason to do so.

I've also been wondering why Mark is using the same IP address for his 
wired and wireless interfaces. Seems to me that each interface should 
have a unique IP address, like the MAC address. I suppose that it might 
make things easier resolving host names. If that's the case, why not 
spoof the MAC address(es) to be the same on both cards, and let DHCP 
handle setting things up? Of course, I think you'd still want to be 
careful to have only one interface active at a time due to leases being 
renewed.

-- 
-Eric 'shubes'
****************************************************
This message has been scanned using Contraxx
Technology Group mail server v8.0.3 and is virus free.
Message sent from Mail Server 3
****************************************************


More information about the PLUG-discuss mailing list