Orientation for Laptops

I carry around my old Vaio and connect it to different subnets. Typing the same commands (ifconfig ....; route delete default; route add default ...; cp /etc/resolv.conf.place /etc/resolv.conf; ...) every time I reconnected got boring, so the stuff went into scripts. I later heard of Felix von Leitner's divine. It sends out fake ARP requests to divine to which network the machine is connected, and takes configured actions depending on the results.

It turns out that it's pretty easy to re-implement this with “standard&ddquo; utilities on OpenBSD. I use arping by Thomas Habets from the ports-tree and ifstated supplied in the OpenBSD source tree. ifstated is not installed in the standard build process, but a simple
cd /usr/src/usr.sbin/ifstated
make && make install

fixes that. The documentation for the config-file ifstated.conf is non-existant, but an example is in /usr/src/etc/ifstated.conf.

You can take my minimal config for multiple networks and adapt it by substituting the name of your interface, the IP/MACs of the hosts in your networks. Works fine in my setup.

Thu, 18 Nov 2004
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