Re: Two fixed network cards

[Derek Broughton <dbroughton@lincsat.com>]

From: "David Z Maze" <dmaze@debian.org>

> ThanhVu Nguyen <thanhvunguyen@psu.edu> writes:
>
> > I have a slightly different situation,  at home my machine has a fixed
> > static address in my local network.  But at school it uses dhcp.  Both
> > places use wired ethernet so I only deal with 1 eth0 here.  So is there
> > a way / or tool that can help me do this task
> ...
> > what I am having now is 2 /etc/network/interface file, one for home ,
> > one for school and I have to change them according to where am I.  An
> > automated task would be good.
>
> Note that you can do things by hand but still only have one
> /etc/network/interfaces file:
>
> # cat /etc/network/interfaces
> iface eth0 inet dhcp
> iface net-home inet static
>       address 192.168.1.17
>       netmask 255.255.255.128
>       broadcast 192.168.1.127
>       gateway 192.168.1.1
> # ifdown eth0
> # ifup eth0=net-home

And Thomas Hood's ifupdown-roaming will handle this automatically, with a single
interfaces file but, if your only way to tell which net you're on is whether or
not you get an IP served by dhcp, there'll be a 30 second (iirc) delay while it
waits for a response from the server (obviously you can change this value in
your dhcp client).  Most of the automatic network detections will look for a
known MAC address, or similar test, to eliminate this delay.