List of Relevant RFC's (Request For Comments)
Here is a list of RFC's that are related to DNS, IP addresses, Mail and internet related protocols.
RFC5966 - DNS Transport over TCP - Implementation Requirements.
RFC5735 - Special Use IPv4 Addresses.
RFC5156 - Special-Use IPv6 Addresses.
RFC4472 - Operational Considerations and Issues with IPv6 DNS.
RFC4408 - Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1.
RFC4343 - Domain Name System (DNS) Case Insensitivity Clarification.
RFC4291 - IP Version 6 Addressing Architecture.
RFC3513 - Internet Protocol Version 6 (IPv6) Addressing Architecture.
RFC3467 - Role of the Domain Name System (DNS).
RFC2822 - Internet Message Format.
RFC2821 - Simple Mail Transfer Protocol.
RFC2606 - Reserved Top Level DNS Names.
RFC2460 - Internet Protocol, Version 6 (IPv6) Specification.
RFC2308 - Negative Caching of DNS Queries (DNS NCACHE).
RFC2219 - Use of DNS Aliases for Network Services.
RFC2182 - Selection and Operation of Secondary DNS Servers.
RFC2181 - Clarifications to the DNS Specification.
RFC2142 - Mailbox Names for Common Services, Roles and Functions.
RFC2050 - Internet Registry IP Allocation Guidelines.
RFC1939 - Post Office Protocol - Version 3.
RFC1918 - Address Allocation for Private Internets.
RFC1912 - Common DNS Operational and Configuration Errors.
RFC1537 - Common DNS Data File Configuration Errors.
RFC1035 - Domain Names - Implementation and Specification.
RFC1034 - Domain Names - Concepts and Facilities.
RFC0937 - Post Office Protocol - Version 2.
RFC0793 - Transmission Control Protocol DARPA Internet Program Protocol Specification.
RFC0791 - Internet Protocol DARPA Internet Program Protocol Specification.
The following RFC's are related, but have been superceded.
RFC3330 - Special-Use IPv4 Addresses.
RFC1725 - Post Office Protocol - Version 3.
RFC0822 - Standard for the Format of ARPA Internet Text Messages.
RFC0821 - Simple Mail Transfer Protocol.