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Port 2377 (Docker Swarm management)

Docker Swarm cluster management traffic between managers and workers.

Registered (user) port, 1024-49151 TCP Containers and Kubernetes Do not expose to the internet

What port 2377 is used for

Docker Swarm cluster management traffic between managers and workers.

Security: should port 2377 be open?

Do not expose to the internet. Allow only between swarm nodes, alongside 7946 and 4789.

IANA assignment

Service nameProtoDescriptionAssigneeReference
swarm TCP RPC interface for Docker Swarm Docker Inc -

Registry dates for this port: registered 2016-12-23.

Check what is listening on port 2377

Linux: is anything listening on TCP 2377?
sudo ss -tlnp 'sport = :2377'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2377
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2377 '
Windows (Command Prompt)
netstat -ano | findstr :2377
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2377 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2377
From Windows
Test-NetConnection HOST -Port 2377

Block port 2377 in the firewall

ufw
sudo ufw deny 2377/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2377 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2377 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2377' -Direction Inbound -Protocol TCP -LocalPort 2377 -Action Block

Related ports

7946Docker Swarm / Serf gossip4789VXLAN2376Docker API (TLS)2375Docker API (plain)2378dali2379etcd client

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.