Copyright Pearson Prentice-Hall 2010 29 PortPrimary Protocol* Application 20TCPFTP Data Traffic 21TCPFTP Supervisory Connection 22TCPSecure Shell (SSH) 23TCPTelnet 25TCPSimple Mail Transfer Protocol (SMTP) 53TCPDomain Name System (DNS) Typically, applications use of either TCP or UDP However, in some cases both TCP and UDP can be used - in such cases, the same port number is used for both
{}