The "ether_line" function from <netinet/ether.h> misparses lines in /etc/ethers
format -- it gets the MAC address wrong.  I will attach two programs, one uses
just "ether_aton" and works fine, one does "ether_line" and loses the high
nibble from each byte in the MAC address.

First one:
$ ./et 00:c0:f0:46:5f:97
orig=00:c0:f0:46:5f:97; new=0:c0:f0:46:5f:97

Second one:
$ echo -n 00:c0:f0:46:5f:97 fooop | ./et2
orig="00:c0:f0:46:5f:97 fooop"; new="0:0:0:6:f:7"/"fooop"

Matthew.