configuring network route

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08-30-2010
Markus_MSC

configuring network route

Hi,

today I tried to configure a network route to a host for testing my network interface.

Code:

route add 192.168.1.15 eth0

As I have to eth interfaces and both interface got their IP from DHCP (192.168.1.11 and 192.168.1.12) and are in the same subnet, I shut the other interface down:

Code:

ifconfig eth1 down

Then I tried to test the interface by doing a ping to 192.168.1.15.

Problem:
When I unplug the cable from eth0 (and eth1 is still plugged) the ping still works. Somehow my linux (it's debian) powers up again eth0 and pings over this port.

How can I stop my linux doing this. I just want to have the route added only on the one interface - not the other.

Is it maybe some case of a default-gateway?

Thanks for your help.
08-31-2010
Kloschüssel

eth1 may has the option auto, which automatically powers it on when a connection can be established. You can look this up here: /etc/network/interfaces
08-31-2010
Markus_MSC

My /etc/network/interfaces has (only for eth0)
allow-hotplug eth0
iface eth0 inet dhcp
08-31-2010
Kloschüssel

Code:

#man 5 interfaces

Quote:

Lines beginning with "allow-" are used to identify interfaces that
should be brought up automatically by various subsytems. This
may be done using a command such as "ifup --allow=hotplug eth0 eth1",
which will only bring up eth0 or eth1 if it is listed in an
"allow-hotplug" line. Note that "allow-auto" and "auto" are synonyms.

Please READ the manual pages if there are some. They are there just for this purpose! :rolleyes:
08-31-2010
Markus_MSC

Thanks for this hint. That was actually the problem!

Yes, I know, RTFM!
08-31-2010
Kloschüssel

True, RTFM and finally SOLVE answered questions. It makes it easier and safes time to everybody.