Registered · Cross-platform

8883 MQTT over TLS

TCP Yes
UDP
SCTP
DCCP

What it is

Secure MQTT.

When / why

Encrypted IoT telemetry — preferred over cleartext 1883.

Protocol status detail

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

Port range

Registered (1024–49151). Assigned by IANA on request; usable without elevated privileges on most systems.

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Firewall rules for port 8883

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 8883

Allow TCP 8883 (MQTT over TLS). 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="8883" protocol="tcp" accept'

Allow TCP 8883 (MQTT over TLS) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 8883 accept

Allow TCP 8883 (MQTT over TLS). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 8883 -j ACCEPT

Allow TCP 8883 (MQTT over TLS). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-mqttovertls-8883 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 8883

Inbound rule for 8883 (MQTT over TLS). 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=8883,ToPort=8883,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 8883 (MQTT over TLS). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-mqttovertls-8883 --direction=INGRESS --action=ALLOW --rules=tcp:8883 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 8883 (MQTT over TLS). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow MQTT over TLS 8883/TCP" dir=in action=allow protocol=TCP localport=8883 remoteip=<source>

Inbound TCP 8883 (MQTT over TLS). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow MQTT over TLS 8883/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 8883 -RemoteAddress <source>

Inbound TCP 8883 (MQTT over TLS). 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.