Well-known · Cross-platform

636 LDAPS

TCP Yes
UDP Assigned
SCTP
DCCP

What it is

LDAP over implicit TLS/SSL.

When / why

Encrypted directory binds and AD authentication. Preferred over cleartext 389.

Protocol status detail

TransportStatusMeaning
TCP Yes Assigned by IANA and standardized, specified, or widely used on this port.
UDP Assigned Assigned by IANA, but not standardized, specified, or widely used on this port.
SCTP Not applicable for this transport.
DCCP Not applicable for this transport.

Port range

Well-known (0–1023). System port for a core service. On Unix-like systems, binding it requires superuser privileges.

Browse all ports →

Firewall rules for port 636

Copy-ready inbound rules for the active transports. Replace every <source> placeholder with the specific host, subnet, or CIDR that should reach this port.

⚠ Unencrypted or unauthenticated by default — prefer a TLS variant or tunnel over VPN/SSH rather than exposing this port directly.

ufw

sudo ufw allow proto tcp from <source> to any port 636

Allow TCP 636 (LDAPS). Replace <source> with the network/host that should reach it.

firewalld

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="636" protocol="tcp" accept'

Allow TCP 636 (LDAPS) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 636 accept

Allow TCP 636 (LDAPS). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 636 -j ACCEPT

Allow TCP 636 (LDAPS). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-ldaps-636 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 636

Inbound rule for 636 (LDAPS). Set <source> to a CIDR; lower priority number = higher precedence.

AWS Security Group

aws ec2 authorize-security-group-ingress --group-id <sg-id> --ip-permissions IpProtocol=tcp,FromPort=636,ToPort=636,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 636 (LDAPS). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-ldaps-636 --direction=INGRESS --action=ALLOW --rules=tcp:636 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 636 (LDAPS). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow LDAPS 636/TCP" dir=in action=allow protocol=TCP localport=636 remoteip=<source>

Inbound TCP 636 (LDAPS). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow LDAPS 636/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 636 -RemoteAddress <source>

Inbound TCP 636 (LDAPS). Replace <source> with a host or subnet.

Rules are generated only for transports marked active for this port. They default to an inbound allow with an explicit source placeholder — never any. Review direction, scope, and rule precedence before applying in production.