Specifying the interface

[Michael Talbot-Wilson]

G'day.  I've had to upgrade the kernel on a gateway box to a private
network and therefore have had to look at iptables for the first time.
Rusty, thanks heaps.

One thing that struck me looking at the examples is the frequency with
which the interface is specified explicitly.

A problem with this is that in general you don't know in advance what it
is, at least in the case of PPP.  Only if you can guarantee that no other
PPP link is going to come up while the one of interest is down can you
know in advance which interface will be used.

For the time being I'm using ipchains.o on Linux 2.3.99-pre5.

Regards,
Mike