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Port 9966 (odnsp)

IANA assigns port 9966 to odnsp: OKI Data Network Setting Protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
odnsp TCP OKI Data Network Setting Protocol Masato Sato -
odnsp UDP OKI Data Network Setting Protocol Masato Sato -

Registry dates for this port: registered 2006-05.

Check what is listening on port 9966

Linux: is anything listening on TCP 9966?
sudo ss -tlnp 'sport = :9966'
Linux: UDP 9966
sudo ss -ulnp 'sport = :9966'
Linux / macOS: which process owns the port
sudo lsof -nP -i :9966
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':9966 '
Windows (Command Prompt)
netstat -ano | findstr :9966
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 9966 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 9966
From Windows
Test-NetConnection HOST -Port 9966
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 9966

Block port 9966 in the firewall

ufw
sudo ufw deny 9966/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 9966 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 9966 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 9966' -Direction Inbound -Protocol TCP -LocalPort 9966 -Action Block
ufw
sudo ufw deny 9966/udp
iptables
sudo iptables -A INPUT -p udp --dport 9966 -j DROP
nftables
sudo nft add rule inet filter input udp dport 9966 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 9966' -Direction Inbound -Protocol UDP -LocalPort 9966 -Action Block

Related ports

9955alljoyn-stm, alljoyn-mcm9956alljoyn9978xybrid-rt9979visweather

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