Cheap Gigabit switch will allow DHCP thru it?

Ben Scott dragonhawk at gmail.com
Sun Dec 30 19:50:55 EST 2007


On Dec 30, 2007 7:15 PM, Jarod Wilson <jarod at wilsonet.com> wrote:
> You also need to change the DEVICE= line in ifcfg-eth0 and ifcfg-eth1 to
> match, and for good measure, should update /etc/modprobe.conf as well to
> alias the right module to the device.

  You won't need to modify /etc/modprobe.conf if you're only swapping
IP configurations between logical devices.  And swapping both will
cancel-out the config changes.

  Bruce currently has something like the following:

SOHO router = onboard, named eth0, configured as 192.168.1.0/24, default gateway
HDHomeRun = card, named eth1, configured as 10.0.0.0/24

  He wants swap the devices connected to the NICs.  That's a physical
change, and is the whole point of this.  :)  So after the cable swap,
we have this:

HDHomeRun = onboard, named eth0, configured as 192.168.1.0/24, default gateway
SOHO router = card, named eth1, configured as 10.0.0.0/24

  Now the problem is, his system will still be trying to talk to the
Internet using the cable that's plugged into his tuner, and MythTV
will be trying to find the tuner where the router is.  That won't work
at all.

  My suggestion (modulo the forgotten config edit) is swap the
configuration being applied to the logical device names.  The result
would be:

HDHomeRun = onboard, named eth0, configured as 10.0.0.0/24
SOHO router = card, named eth1, configured as 192.168.1.0/24, default gateway

  The other approach, originally suggested by MOD, would be to swap
the names the kernel is assigning to the devices:

SOHO router = onboard, named eth1, configured as 192.168.1.0/24, default gateway
HDHomeRun = card, named eth0, configured as 10.0.0.0/24

  Thinking about it, I actually like the later method better, as it
bypasses any firewall/DHCP/etc config file changes to update devices.
You just change what each device is being called.

-- Ben


More information about the gnhlug-discuss mailing list