Internet Protocol Standards  
 

Throughout this documentation, the term protocol refers to a set of rules that define how computers communicate with one another. There are two types of protocols which are important when working with network applications: transport protocols and application protocols.

Transport protocols define how data is exchanged between systems. The two transport protocols discussed in this guide are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). These protocols provide the underlying communication channel used by network applications.

Application protocols are built on top of transport protocols to perform specific tasks. For example, the File Transfer Protocol (FTP) is used to transfer files, while the Simple Mail Transfer Protocol (SMTP) is used to send email messages. Other common application protocols include HTTP for web services and SSH for secure remote access.

The Internet application protocols are defined in standards documents called RFCs (Request For Comments) which are maintained by the Internet Engineering Task Force. The following protocols standards are implemented by the SocketTools controls:

File Transfer

Protocol Standards Description
FTP RFC 959, RFC 1579, RFC 2228, RFC 2428, RFC 3659 File Transfer Protocol including security, NAT/firewall support, and extended directory services.
SSH / SFTP RFC 4251, RFC 4252, RFC 4253, RFC 4254 Secure Shell protocol used for secure remote access and file transfers.
TLS RFC 8446 Transport Layer Security used by FTPS and other secure protocols.

Web Services and REST APIs

Protocol Standards Description
HTTP RFC 9110, RFC 9112
Legacy: RFC 1945, RFC 2616
Hypertext Transfer Protocol used by websites, REST APIs and cloud services.
URI / URL RFC 3986
Legacy: RFC 1738
Uniform Resource Identifier syntax and resource naming conventions.
TLS RFC 8446 Secure transport protocol used by HTTPS services and APIs.
Compression RFC 1951, RFC 1952 Deflate and GZIP compression formats commonly used by HTTP servers.

Electronic Mail

Protocol Standards Description
SMTP RFC 5321, RFC 1869, RFC 6531
Legacy: RFC 2821
Message submission and transfer protocol with service extensions and internationalized email support.
Message Format RFC 5322
Legacy: RFC 822
Internet message header and body format.
MIME RFC 2045, RFC 2049, RFC 2183, RFC 2231 Multipurpose Internet Mail Extensions including attachments, content types and parameter encoding.
POP3 RFC 1939 Post Office Protocol Version 3.
IMAP4 RFC 3501 Internet Message Access Protocol Version 4.
TLS RFC 8446 Secure transport protocol used by SMTPS, POP3S and IMAPS.

Network News (Usenet)

Protocol Standards Description
NNTP RFC 3977
Legacy: RFC 977, RFC 2980
Network News Transfer Protocol used to access and manage Usenet servers.
TLS RFC 8446 Secure transport protocol used by NNTPS servers.

Internet Infrastructure

Protocol Standards Description
DNS RFC 1034, RFC 1035 Domain Name System used to resolve host names and service records.
ICMP RFC 792 Internet Control Message Protocol used by Ping and network diagnostics.
IPv6 RFC 8200 Internet Protocol Version 6.
Time Protocol RFC 868 Simple network time service.