Registered · Cross-platform

7946 Docker Swarm gossip

TCP Unofficial
UDP Unofficial
SCTP —
DCCP —

What it is

Swarm node-to-node gossip (TCP+UDP).

When / why

Container overlay membership between Swarm nodes.

Protocol status detail

TransportStatusMeaning
TCP Unofficial Not assigned by IANA, but standardized, specified, or widely used on this port.
UDP Unofficial Not assigned by IANA, but standardized, specified, or widely used on this port.
SCTP — Not applicable for this transport.
DCCP — Not applicable for this transport.
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Port range

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

Browse all ports →

Firewall rules for port 7946

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 7946

Allow TCP 7946 (Docker Swarm gossip). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 7946

Allow UDP 7946 (Docker Swarm gossip). 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="7946" protocol="tcp" accept'

Allow TCP 7946 (Docker Swarm gossip) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="7946" protocol="udp" accept'

Allow UDP 7946 (Docker Swarm gossip) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 7946 accept

Allow TCP 7946 (Docker Swarm gossip). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 7946 accept

Allow UDP 7946 (Docker Swarm gossip). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 7946 -j ACCEPT

Allow TCP 7946 (Docker Swarm gossip). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 7946 -j ACCEPT

Allow UDP 7946 (Docker Swarm gossip). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-dockerswarmgossip-7946 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 7946

Inbound rule for 7946 (Docker Swarm gossip). 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=7946,ToPort=7946,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 7946 (Docker Swarm gossip). Replace <source-cidr> (e.g. 10.0.0.0/16).

aws ec2 authorize-security-group-ingress --group-id <sg-id> --ip-permissions IpProtocol=udp,FromPort=7946,ToPort=7946,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 7946 (Docker Swarm gossip). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-dockerswarmgossip-7946 --direction=INGRESS --action=ALLOW --rules=tcp:7946,udp:7946 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 7946 (Docker Swarm gossip). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow Docker Swarm gossip 7946/TCP" dir=in action=allow protocol=TCP localport=7946 remoteip=<source>

Inbound TCP 7946 (Docker Swarm gossip). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow Docker Swarm gossip 7946/UDP" dir=in action=allow protocol=UDP localport=7946 remoteip=<source>

Inbound UDP 7946 (Docker Swarm gossip). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow Docker Swarm gossip 7946/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 7946 -RemoteAddress <source>

Inbound TCP 7946 (Docker Swarm gossip). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow Docker Swarm gossip 7946/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 7946 -RemoteAddress <source>

Inbound UDP 7946 (Docker Swarm gossip). 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.