HOWTO write a udev rule to awaken fetchmail after eth0 is up

[Paulo M C Aragão <yagpaulo-listas@yahoo.com>]

Hi,

I'm trying to write a udev rule to awaken a system-wide fetchmail daemon 
whenever eth0 is brought up, but I'm lost about which event to capture.

Before udev, I did this in /etc/network/interfaces:

iface eth0 inet dhcp
    post-up /etc/init.d/fetchmail start || true
    pre-down /etc/init.d/fetchmail stop || true

I'd like to do functionally the same with udev.

I've read the docs that come with udev and changed this line in 
/etc/udev/hotplug.rules:

RUN+="/lib/udev/logger.agent"

to get a feeling of what events are produced, but I'm still not sure of what 
event I should capture.

Has anybody done this and could share the tips ?

Thanks
Paulo