Best (and short) book on network security

Question

For Linux and maybe other platforms. Could you suggest?

Answer 1

See here some recommendations:

http://stackoverflow.com/questions/1211521/what-are-good-books-on-computer-networks, http://stackoverflow.com/questions/365495/network-security

I personally liked this one for its pragmatism and use of commonly found software: Linux Firewalls: Attack Detection and Response with iptables, psad, and fwsnort

Another good one IMO (good coverage): Hardening Linux