MULTINET4 MULTI-PORT SERIAL SERVER & MANAGED SWITCH – INSTRUCTION MANUAL
A–1
Multinet4 Multi-Port Serial Server
& Managed Switch
Chapter A: Port and Type
Reference
Digital Energy
Multilin
Port and Type Reference
A.1 Well Known TCP/UDP Network Ports
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are members of the
Internet Protocol Suite. They enable the transmission of data among networked computers
by directing traffic to ports associated with specific functions.
TCP is a connection-oriented protocol; that is, it creates an identified connection from
client to server for the transmission of data. TCP provides a very reliable interface to a
specified port.
UDP is a simpler message-based connectionless protocol; that is, UDP simply sends a
packet of data to a specified address and port. UDP does not provide the reliability of TCP
but it can deliver data with less overhead.
Network port numbers are assigned to specific uses by the Internet Assigned Numbers
Authority (IANA). Port numbers 0-1023 are called Well Known Ports and have standard
uses, such as port 80 for HTML traffic. Port numbers 1024-49151 are reserved for
Registered Ports, and port numbers 49152-65535 are the dynamic ports which can be put
to any use.
Comprehensive lists of the conventional uses of all Well Known and Registered ports are
available on the internet and in publications. The table below is a partial list of official Well
Known ports.
Table A–1: Well Known Ports
Port
Description
0/TCP,UDP
Reserved
1/TCP,UDP
TCPMUX (TCP port service multiplexer)
5/TCP,UDP
RJE (Remote Job Entry)