636 ldap protocol over TLS/SSL (was sldap) - System Port

636 is a System Port. Transport Protocol TCP UDP , 636 Service Name ldaps, Service Name Description: ldap protocol over TLS/SSL (was sldap).

Port	Protocol	Service Name	Description	Source
636	TCP UDP	ldaps	ldap protocol over TLS/SSL (was sldap)	IANA
636	TCP UDP		Lightweight Directory Access Protocol over TLS/SSL (LDAPS),Official	wikipedia
636	TCP UDP		Mac OS X RPC-based services, Used by NetInfo, for example	Apple.com
636	TCP		Secure LDAP	Apple.com
636	TCP UDP	ldaps	ldap protocol over TLS/SSL (was sldap)	bekkoame

Port	Service Name	Description
587	submission	Message Submission
838		Unassigned
844		Unassigned
971		Unassigned
1023		Reserved
1284	iee-qfx	IEE-QFX
1383	gwha	GW Hannaway Network License Manager
1555	livelan	livelan
1920	can-ferret	IBM Tivoli Directory Service - FERRET
2102	zephyr-srv	Zephyr server

A port is an endpoint of communication in an operating system. While the term is also used for hardware devices, in software it is a logical construct that identifies a specific process or a type of service.

Port numbers are assigned in various ways, based on three ranges: System Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private Ports (49152-65535);

The Well Known Ports are assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users. Ports are used in the TCP [RFC793] to name the ends of logical connections which carry long term conversations. For the purpose of providing services to unknown callers, a service contact port is defined. This list specifies the port used by the server process as its contact port. The contact port is sometimes called the "well-known port". To the extent possible, these same port assignments are used with the UDP [RFC768]. The range for well-known ports managed by the IANA is 0-1023.
DYNAMIC AND/OR PRIVATE PORTS Registered Ports are those from 1024 through 49151.
The Dynamic and/or Private Ports are those from 49152 through 65535