add 'ISC's Knowledgebase'

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -867,6 +867,7 @@ performance of any of your sites from across the globe.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/digitalocean/nginxconfig.io"><b>nginxconfig.io</b></a> - NGINX config generator on steroids.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://infosec.mozilla.org/guidelines/openssh"><b>openssh guideline</b></a> - is to help operational teams with the configuration of OpenSSH server and client.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://gravitational.com/blog/ssh-handshake-explained/"><b>SSH Handshake Explained</b></a> - is a relatively brief description of the SSH handshake.<br>
+&nbsp;&nbsp;:small_orange_diamond: <a href="https://kb.isc.org/docs/using-this-knowledgebase"><b>ISC's Knowledgebase</b></a> - you'll find some general information about BIND 9, ISC DHCP, and Kea DHCP.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://packetlife.net/"><b>PacketLife.net</b></a> - a place to record notes while studying for Cisco's CCNP certification.<br>
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