Lightweight Directory Access Protocol or LDAP is used to authenticate and authorize users. LDAP is used in different infrastructures like Windows Domain, Linux, Network etc. LDAP uses different port numbers like 389 and 636.
TCP 389 For LDAP
The well-known port for LDAP is TCP 389. Both UDP and TCP transmission can be used for this port. We can use this port for unsecured and unencrypted LDAP transmission.
TCP and UDP 636 Secure or SSL LDAP
Security is an important part of the network protocols. LDAP is not a secure protocol if we do not implement extra security measures. LDAPS is a secure version of the LDAP where LDAP communication is transmitted over an SSL tunnel. Also TCP and UDP 636 can be used for LDAPS secure transmission.