IETF Internet Drafts  
   List of documents organized by alphabetized subjects.
   http://www.ietf.org/1id-abstracts.html

Active IETF Working Groups  
   A directory of the Internet Engineering Task Force groups and their web pages.
   http://www.ietf.org/html.charters/wg-dir.html

Internet protocols  
   General comments on protocol design, and good reference material on a few protocols (especially mail-related; also ftp, time, and misc) by Dan Bernstein.
   ftp://koobera.math.uic.edu/www/proto.html

Port Numbers and Services Database  
   Well known port numbers for TCP and UDP, from Internet Assigned Numbers Authority (IANA).
   http://www.sockets.com/services.htm

RFC Sourcebook  
   Description of protocols, file formats, glossary of terms, RFCs.
   http://www.networksorcery.com/enp/

Protocols.com  
   Features an overview of various networking and mobile communications protocols, white papers, and links of interest.
   http://www.protocols.com/

XNS.org  
   Independent organization managing the eXtensible Name Service, an open protocol and open-source platform for universal addressing, automated data exchange, and privacy control. Includes an overview, charter, history, and specifications.
   http://www.xns.org/

Internet Encyclopedia  
   Overview of Internet protocols.
   http://www.freesoft.org/CIE/Topics/73.htm

The Kermit Project  
   A protocol that transfers text and binary files without errors between diverse types of computers over potentially hostile communication links, and a suite of communications software programs; Columbia University.
   http://www.kermit-project.org/

Free Protocols Foundation  
   Independent public forum supporting patent-free protocols. Includes policies, papers, a mission statement, and a list of free protocols.
   http://www.freeprotocols.org/