activating an unconfigured interface using /etc/network/interfaces...?

[Matthew Whitworth]

I have a dual-homed host spanning two networks and I would like to leave 
one of its interfaces unconfigured so that I can use libpcap 
applications on that network unobserved.  I can do this using the 
command string "ifconfig eth1 0.0.0.0 up", but I was wondering if there 
was a way to do this using the /etc/network/interfaces file and the 
ifup/ifdown commands.  If there is, I can't seem to get the syntax.

Thanks,
Matthew