Know how to use "fewer" and "less"? Find out.
The RFC STD 2 documenting the currently assigned values from several series of numbers used in network protocol implementations. This RFC is updated periodically and, in any case, current information can be obtained from the Internet Assigned Numbers Authority (IANA). If you are developing a protocol or application that will require the use of a link, socket, port, protocol, etc., you should contact the IANA to receive a number assignment.