Registered · Cross-platform

4222 NATS

TCP Unofficial
UDP
SCTP
DCCP

What it is

NATS messaging server.

When / why

Cloud-native pub/sub. Secure with TLS/auth.

Protocol status detail

TransportStatusMeaning
TCP Unofficial Not assigned by IANA, but 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 4222

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 4222

Allow TCP 4222 (NATS). 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="4222" protocol="tcp" accept'

Allow TCP 4222 (NATS) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 4222 accept

Allow TCP 4222 (NATS). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 4222 -j ACCEPT

Allow TCP 4222 (NATS). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-nats-4222 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 4222

Inbound rule for 4222 (NATS). 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=4222,ToPort=4222,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 4222 (NATS). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-nats-4222 --direction=INGRESS --action=ALLOW --rules=tcp:4222 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 4222 (NATS). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow NATS 4222/TCP" dir=in action=allow protocol=TCP localport=4222 remoteip=<source>

Inbound TCP 4222 (NATS). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow NATS 4222/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 4222 -RemoteAddress <source>

Inbound TCP 4222 (NATS). 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.