Security
Risk: Low
Port 636 — LDAPS (Secure LDAP over SSL)
Port 636 is the official port for LDAPS (LDAP over SSL), providing encrypted transport for enterprise directory lookups, user authorization, and password management.
PORT NUMBER
636
PROTOCOL
TCP
DEFAULT PROCESS
slapd, lsass.exe
FIREWALL TARGET
636/tcp
Instant Terminal Fixes for Port 636
macOS & Linux Terminal
1. Check who is listening on port 636:
sudo lsof -i :636 || sudo ss -tulpn | grep ":636 "2. Kill process occupying port 636 (EADDRINUSE fix):
sudo systemctl stop slapd3. UFW Firewall Allow rule:
sudo ufw allow 636/tcpWindows PowerShell (Admin)
1. Check listening port:
Get-NetTCPConnection -LocalPort 6362. Force kill process on port 636:
Stop-Service NTDS -Force -ErrorAction SilentlyContinue3. Docker Port Forwarding Mapping:
docker run -p 636:636 -d osixia/openldap:latestCommon Error Encountered
LDAP error: TLS negotiation failed connecting to port 636.
Security Advisory & Hardening
Preferred standard over cleartext port 389. Ensure CA certificates are deployed across client servers to validate trust chains.
Frequently Asked Questions
Port 636 Questions & Answers
Common questions regarding default services, kill commands, and firewall configurations.
Port 636 is commonly used for LDAPS (Secure LDAP over SSL). Port 636 is the official port for LDAPS (LDAP over SSL), providing encrypted transport for enterprise directory lookups, user authorization, and password management.