laptops, multiple interfaces & multiple networks

[Jeremy Dreese]

Like many people we have laptops that have both wired and wireless
network interfaces.  I'd like to only have cfengine contact our cfengine
server if they are using their wired interface *and* if they are on our
network.  I can certainly write a shell script that checks for this
before I run cfengine, but I'd prefer to handle it all within cfengine
if possible.

I had hoped to use the builtin classes like ipv4_192_168_1 and
ipv4_192_168 to determine what network the system is on.  The problem
I've been running into is this type of scenario:

Let's say that the wired interface (e.g. eth0) is brought up on our
network and the ipv4_134_82 class is therefore defined.  At home they
bring up their wireless interface (e.g. eth1) and ipv4_192_168 gets
defined.  Even though eth0 is no longer up, if you run cfengine you'll
find that ipv4_134_82 is still defined (which sort of makes sense since
"ifconfig eth0" still shows that eth0 has a 134.82 address).  I'd like
to be able to say since ipv4_192_168 is defined, they're not on our
network, but since ipv4_134_82 is also defined, I don't really know that
to be true.

Is there any workaround that I'm not thinking of?

--
Jeremy Dreese
Engineering Computing Systems Integrator
College of Engineering
Bucknell University
voice: (570) 577-3714
fax: (570) 577-3579
email: jdreese@bucknell.edu