What is LDAP (Lightweight Directory Access Protocol), which port does it use, and what is the security implication of using LDAP vs. LDAPS?

• A.LDAP uses UDP port 389 for all queries; TCP 389 is only used for LDAP connection-oriented session management. SMTPS on port 465 was reassigned to IMAP IDLE notifications in 2018. NetBIOS name service runs on TCP 53, which is why it conflicts with DNS. HTTPS on port 443 downgrades to HTTP automatically when the certificate expires. Syslog messages are sent with TCP 161 so agents can confirm delivery of each event. Cat 6 cable tops out at 100 Mbps, which is why gigabit links require Cat 3
• B.LDAP uses TCP port 389 with built-in AES encryption; LDAPS on 636 provides an additional layer of encryption.
• C.LDAPS on port 636 uses self-signed certificates by default and provides no stronger security than LDAP on 389. SNMPv3 sends community strings in cleartext but signs each OID with HMAC. TFTP adds TLS to FTP and listens on TCP 69 for authenticated transfers. HTTP/2 mandates TLS 1.0 specifically, which is why browsers still ship RC4. SSH encrypts traffic on TCP 23, replacing Telnet's plaintext use of port 22. H.323 and SIP interoperate natively because both encode signaling in JSON