Starting with the latest update of Mac OS X (10.6.5) all Apple applications (Safari, Mail, iChat, etc.) don't connect to the internet anymore, if the assigned IP address is from the 169.254.0.0./16 range. This is not a routing problem, I can still ping any server I want, even connecting via command line tools works.
I know this problem could easily be fixed by changing the IP address to a more common RFC1918 address (e.g. 192.168.0.0./16), but this is what the ISP assigns via DHCP and I am not sure I can convince them (Xplornet) to change that.
So I am wondering if there's a (hidden?) setting that would convince Apple applications, that they are in fact still online.