static arp setup for Linux

1) edit /etc/ethers, and add lines as following:
192.168.1.10 00:12:34:56:78:9A
2) run `arp -f`. and you can add this line into /etc/rc.local for startup.
3) use `arp -d ..` to delete specific entries.

REFERENCES:
http://blog.fashion-style.com.tw/2008/05/13/linux_161816_arp_virus/
http://ceasarfree.blogspot.com/2010/09/linuxarp.html