Registered · Cross-platform

4843 OPC UA over TLS

TCP Yes
UDP
SCTP
DCCP

What it is

OPC UA over TLS/SSL.

When / why

Encrypted industrial telemetry.

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 4843

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

ufw

sudo ufw allow proto tcp from <source> to any port 4843

Allow TCP 4843 (OPC UA 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="4843" protocol="tcp" accept'

Allow TCP 4843 (OPC UA over TLS) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 4843 accept

Allow TCP 4843 (OPC UA over TLS). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 4843 -j ACCEPT

Allow TCP 4843 (OPC UA over TLS). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-opcuaovertls-4843 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 4843

Inbound rule for 4843 (OPC UA 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=4843,ToPort=4843,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 4843 (OPC UA over TLS). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-opcuaovertls-4843 --direction=INGRESS --action=ALLOW --rules=tcp:4843 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 4843 (OPC UA over TLS). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow OPC UA over TLS 4843/TCP" dir=in action=allow protocol=TCP localport=4843 remoteip=<source>

Inbound TCP 4843 (OPC UA over TLS). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow OPC UA over TLS 4843/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 4843 -RemoteAddress <source>

Inbound TCP 4843 (OPC UA 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.