Two elementary questions on LANs

[Timothy Murphy]

Ed Greshko wrote:

>> I'm sure that is true.
>> But where does the machine keep the old IP?
>> I couldn't find it anywhere.
> 
> That information is kept in the lease information and is why I've been
> trying to elicit explicit information with explicit question.

Thanks for your continuing help.
As I mentioned, I searched (grep -r 192.168.1.7) on the laptop
for the address that kept re-appearing, in /etc and /var/lib
and it did not appear in either.
Of course it might have been in some other form, eg as an octal number.

> Now, I really want to know what interface you want to concentrate
> on.....  Is it your wired LAN, eth1...or your wireless wlan0?  You've
> confused me by talking about both.

I have a single LAN consisting of a server
linked by ethernet to a router
and a number of laptops linked to the router by WiFi.
The interface on the CentOS server is called eth1,
and that on the Fedora laptops is called wlan0.
(There are also a few other devices on the LAN,
a Windows XP laptop, a Linksys camera and an iPhone.)

The server is also linked on eth0 to a Billion ADSL modem/router
and so to the internet.

> Do you have 2 dhcp servers on the same subnet?

No.
I was running (or rather, hoping to run) dhcp on the Linksys router.
Now I am running it on the server.

The simplest explanation of my problem (now over)
is that the dhcp server on the Linksys router
was sendout out confusing information.
It didn't seem possible, at first glance,
to get information about what was going on in the router.
I have another, identical, Linksys router (not here)
except that that one is running the dd-wrt system
while this one is running the software that comes with the device.
The dd-wrt version gives copious information,
with log files, lists of connected devices, etc.

My basic error, I think, was to assume that
this router would behave in the same way.



-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland