The "RFC editor" lists all the RFCs. Ones called "Standards" are the ones in wide use for major protocols like IP or TCP.
RFCs - http://www.rfc-editor.org/

Internic for information about who can assign names:
Commerce Dept licenses service.

This includes a list of authorized sellers of Internet namesi at this link:
https://www.internic.net/alpha.html

"whois" lookup service - to see who owns domain names https://whois.icann.org/en

Command line "whois" in LINUX.

Command line "nslookup" in Windows: "nslookup /help" for info

Command line "nslookup" in LINUX. Do "man nslookup" or refer to text.

TCP Well known ports - http://www.iana.org/assignments/port-numbers

IP Address assignments http://www.iana.org/ipaddress/ip-addresses.htm

Find out YOUR IP address as seen by the outside world (i.e. outside of your NAT environment):
https://www.whatismyip.com/ip-address-lookup/

Find out who owns a certain IP address:
http://itools.com/tool/arin-whois-domain-search