C++

ISO Standard – https://isocpp.org/std/the-standard
C++ reference – http://www.cplusplus.com/reference/
C++ reference – http://en.cppreference.com/w/
Core guidelines – https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md
Optimisations – http://www.agner.org/
Compiler explorer – https://godbolt.org

Business

FIX dictionary – http://www.onixs.biz/fix-dictionary/4.2/index.html
Monty Hall – http://www.mathwarehouse.com/monty-hall-simulation-online/

NAS

DNS AdBlocker – https://synologytweaks.wordpress.com/2015/08/23/use-synology-as-an-ad-blocker/
DDNS to DNS – http://www.ianatkinson.net/computing/ddns.htm
lets encrypt – https://letsencrypt.org/
Optware – http://www.nslu2-linux.org/wiki/pmwiki.php?pagename=Optware/HomePage
Categorise website – http://sitereview.bluecoat.com/sitereview.jsp
Domain price comparison tool – https://www.domcomp.com
Forward domain level email – http://improvmx.com
SMTP postfix – https://forum.synology.com/enu/viewtopic.php?t=128179