B.2. 安全性参考文献
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-  **The Book of PF: A No-Nonsense Guide to the OpenBSD Firewall**, Third Edition, published by `No Starch Press <https://nostarch.com/pf3>`__, 2014. ISBN: 978-1593275891

-  **SSH Mastery: OpenSSH, PuTTY, Tunnels, and Keys**, Second Edition, 2018. ISBN: 978-1642350029