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Port 564 (9pfs)

IANA assigns port 564 to 9pfs: plan 9 file service.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
9pfs TCP plan 9 file service - -
9pfs UDP plan 9 file service - -

Check what is listening on port 564

Linux: is anything listening on TCP 564?
sudo ss -tlnp 'sport = :564'
Linux: UDP 564
sudo ss -ulnp 'sport = :564'
Linux / macOS: which process owns the port
sudo lsof -nP -i :564
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':564 '
Windows (Command Prompt)
netstat -ano | findstr :564
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 564 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 564
From Windows
Test-NetConnection HOST -Port 564
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 564

Block port 564 in the firewall

ufw
sudo ufw deny 564/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 564 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 564 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 564' -Direction Inbound -Protocol TCP -LocalPort 564 -Action Block
ufw
sudo ufw deny 564/udp
iptables
sudo iptables -A INPUT -p udp --dport 564 -j DROP
nftables
sudo nft add rule inet filter input udp dport 564 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 564' -Direction Inbound -Protocol UDP -LocalPort 564 -Action Block

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