Why won my network interface work now that Ive upgraded to NetBSD 1.3?
This is because the network interface file format and naming convention have changed. Instead of hostname.ae0, you now have a file named ifconfig.xxN where xx is one of ae, sn, or mc depending on your networking hardware, and N is the number of the interface (probably 0 unless you have multiple interfaces of the same type). The contents of this new file are simply the arguments that you would give to the ifconfig command to bring up the interface manually.