Once issued, RFCs do not change. Protocol revisions are documented by issuing new RFCs. The older RFCs are still available, but are said to be obsoleted by the newer RFCs.
At the time of this writing (January 1996), there are almost 2000 RFCs in existance, dating back to the formative stages of the ARPANET in the 1970s. We have selected some of the most important and informative RFCs for inclusion in the TCP/IP encyclopedia, but this set is by no means exhaustive.
Most RFCs are available as large text files, with graphics made out of typewriter characters. The RFCs presented here have been broken down into smaller sections and converted into an HTML format for presentation over the Web. Care has been taken to preserve the content of the RFCs throughout, and the original text version of each RFC is available via a hyperlink from its Table of Contents.
The on-line search form above searches the RFC index for all RFCs through RFC 1998. Each RFC has a hyperlink associated with it pointing either at the encyclopedia version, or, if no encyclopedia version exists, to the original files at ds.internic.net. The original index (rfc-index.txt - 280 KB) is also available.
Other good places to start are the Internet Offical Standards RFC (RFC 1880), the Assigned Numbers RFC (RFC 1700), the Requirements for Internet Hosts (RFC 1122 and RFC 1123), and the Requirements for Internet Routers (RFC 1812).