Port 7946Cluster Gossip (Serf / Docker Swarm)

Used for cluster-node discovery and gossip by Docker Swarm and HashiCorp Serf.

transport: tcp · udp
in transit: cleartext
assignment: unofficial
risk: 6/10
lookups: 0

Technical Details

what runs on :7946

This port is used by more than one implementation, so there is no single wire protocol or handshake for it. Docker Swarm uses both TCP and UDP on 7946 for node communication and discovery; its other commonly required ports are TCP 2377 for cluster management and UDP 4789 for overlay network traffic. Serf also uses TCP and UDP 7946 by default for gossip. Serf encryption is configurable rather than enabled by default.

Security Information

exposure of :7946

risk score

6/ 10risk

treat as sensitive. widely scanned and regularly exploited when reachable — restrict it to known sources.

network services averages 2.6 across 2,029 ports — this one sits 3.4 above.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

unofficial

used by convention, not registered — what answers here varies by deployment

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Do not expose this port broadly to the internet: restrict it to the cluster nodes that need to communicate. The exact risk depends on the software using it; Serf gossip is not encrypted by default, while Docker Swarm documents encrypted management communication between nodes. Untrusted access to cluster communication ports can expose membership information or disrupt cluster operations.

Record

iana registry entry

port: :7946
service: Cluster Gossip (Serf / Docker Swarm)
transport: TCPUDP
encryption: cleartext
assignment: convention only
risk: 6/10risk
category: Network Services System
usage: Docker Swarm nodes use TCP and UDP port 7946 for communication and network discovery between nodes. HashiCorp Serf also uses port 7946 for cluster gossip; it is not an IANA-registered assignment.
lookups: 0rank 993
added: 2026-11-12
updated: 2026-11-12
references: Docker Swarm tutorial: Open protocols and ports between the hosts
HashiCorp Serf: Architecture
IANA Service Name and Transport Protocol Port Number Registry

Something wrong?

This record is maintained by the engineers who use port 7946. Every field on it is editable — change what's wrong, say how you know, and a reviewer publishes it, usually within a minute. Last touched 2026-11-12.

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edit this record →back to the registry

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risk mix of the 8 listed

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Port :7946Cluster Gossip (Serf / Docker Swarm)

Technical Details

Security Information

Related Ports

Port 7946Cluster Gossip (Serf / Docker Swarm)