Port 6653 (openflow)

IANA assigns port 6653 to openflow: OpenFlow.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

openflow TCP OpenFlow Open Networking Foundation -

openflow UDP OpenFlow Open Networking Foundation -

Registry dates for this port: registered 2013-07-18.

Linux: is anything listening on TCP 6653?

sudo ss -tlnp 'sport = :6653'

Linux: UDP 6653

sudo ss -ulnp 'sport = :6653'

Linux / macOS: which process owns the port

sudo lsof -nP -i :6653

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':6653 '

Windows (Command Prompt)

netstat -ano | findstr :6653

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6653 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 6653

From Windows

Test-NetConnection HOST -Port 6653

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 6653

ufw

sudo ufw deny 6653/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 6653 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 6653 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 6653' -Direction Inbound -Protocol TCP -LocalPort 6653 -Action Block

ufw

sudo ufw deny 6653/udp

iptables

sudo iptables -A INPUT -p udp --dport 6653 -j DROP

nftables

sudo nft add rule inet filter input udp dport 6653 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 6653' -Direction Inbound -Protocol UDP -LocalPort 6653 -Action Block

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