Bookmarks
( src: http://repos.hostek.io/hostek-toolbar/main.html )

Blacklist Checkers
http://multirbl.valli.org/ Notes: Checks 300+ Blacklists
http://mxtoolbox.com/blacklists.aspx Notes: Tests most common BLs

Mail
http://vamsoft.com/support/tools/spf-policy-tester
http://www.dnsstuff.com/tools
https://support.google.com/a/answer/174125?hl=en Notes: Gmail/Google MX
http://bit.ly/1am7TIZ Notes: Outlook/Hotmail MX

Utilities
http://htaccess.madewithlove.be/
https://sitecheck.sucuri.net/
http://www.yougetsignal.com/
https://howsecureismypassword.net/
http://explainshell.com/

Networking
https://systems.hostek.com/wiki/Firewall_ports

Security
http://map.ipviking.com/ Notes: Live Attacks
http://arstechnica.com/security/ Notes: Current Security/Attack News
http://www.infoworld.com/category/security/ Notes: Current Security/Attack News

SSL
https://www.ssllabs.com/ssltest/index.html
https://www.sslshopper.com/ssl-checker.html
https://ssltools.geotrust.com/checker/views/certCheck.jsp

Reference
http://www.iis.net/
https://documentation.canel.net/
http://devdocs.io/
http://www.w3schools.com/
http://www.askapache.com/htaccess/htaccess.html


Bonus: http://bit.ly/JCAXzb