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Tech Note #81: Some Well-Known Ports
1998 Bionic Buffalo Corporation; All Rights Reserved.
       11 November 1998
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Note: DSM-CC defines several protocols, including those above, plus the User-User
protocol. Most implementations of DSM-CC use IIOP for the User-User protocol. The
port assignments for IIOP are listed below.
HTTP (Hypertext Transfer Protocol)
Port 80: HTTP
HTTP is the common protocol used among WWW browsers and clients. The
specifications can be found at the World Wide Web Consortium’s site,
IIOP (Internet Inter-ORB Protocol)
Port 535: IIOP
IIOP is the TCP/IP flavour of the protocol defined by CORBA, the Common Object
Request Broker Architecture. The specifications are maintained by the Object
Management Group (OMG), at
LDAP (Lightweight Directory Access Protocol)
Port 389: LDAP
LDAP is a lightweight protocol used for access to the X.500 Directory. It is defined by
RFC 1777.
NTP (Network Time Protocol)
Port 123: NTP
NTP is used to distribute the current time and date. It is defined by RFC 1305. A
lightweight variant, the Simple Network Time Protocol (SNTP), is defined by RFC
2030. In multicast mode, the IPv4 group address used is
TOAD (Tractable Object Advertising and Discovery)
Port 2669: TOAD
TOAD is used for object advertising and discovery. A description is to be found in Tech
Note #37: Introduction to the TOAD Protocol