CyberHunter
Local dataset, no network
// Other services

Port 9956: Alljoyn Name Service

Port 9956 is assigned by IANA to alljoyn (Alljoyn Name Service).

9956

How alljoyn works

Other services
client:9956alljoynresponse client:9956alljoynresponse

The client sends a request to port 9956 and the alljoyn service answers.

Transport
UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
01 Security

Is port 9956 dangerous?

We have no specific security note for port 9956. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 9956

ServicePortTransportDescriptionReferenceUpdated
alljoyn 9956 UDP Alljoyn Name Service - 2011-12-21
-9956-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 9956, and is it reachable?

Linux

sudo ss -ltnup 'sport = :9956'      # process listening on 9956
sudo lsof -nP -i :9956

macOS

sudo lsof -nP -i :9956

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9956 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 9956
netstat -ano | findstr :9956

From another machine

nmap -p 9956 -sV <host>
sudo nmap -sU -p 9956 <host>
nc -zv <host> 9956

Block it in the firewall

sudo ufw deny 9956/udp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 9956" -Direction Inbound -LocalPort 9956 -Protocol UDP -Action Block  # Windows
04 FAQ
What is port 9956 used for?

Port 9956 is assigned by IANA to alljoyn (Alljoyn Name Service).

Is port 9956 TCP or UDP?

Port 9956 is registered for UDP.

Is it safe to open port 9956?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 9956 is open?

On Linux run "ss -ltnup 'sport = :9956'", on macOS "lsof -nP -i :9956", and on Windows "netstat -ano | findstr :9956" to see the local process. From another machine, "nmap -p 9956 <host>" shows whether it is reachable.

05 Related

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