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Port 9956 (alljoyn)

IANA assigns port 9956 to alljoyn: Alljoyn Name Service.

Registered (user) port, 1024-49151 UDP

Port 9956 is normally used over UDP; the checker tests TCP only, so a "filtered" result does not mean the UDP service is down.

IANA assignment

Service nameProtoDescriptionAssigneeReference
alljoyn UDP Alljoyn Name Service Qualcomm Innovation Center -

Registry dates for this port: registered 2011-12-21.

Check what is listening on port 9956

Linux: UDP 9956
sudo ss -ulnp 'sport = :9956'
Linux / macOS: which process owns the port
sudo lsof -nP -i :9956
Windows (Command Prompt)
netstat -ano | findstr :9956
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 9956

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 9956

Block port 9956 in the firewall

ufw
sudo ufw deny 9956/udp
iptables
sudo iptables -A INPUT -p udp --dport 9956 -j DROP
nftables
sudo nft add rule inet filter input udp dport 9956 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 9956' -Direction Inbound -Protocol UDP -LocalPort 9956 -Action Block

Related ports

9954hinp9955alljoyn-stm, alljoyn-mcm9966odnsp9978xybrid-rt

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