CyberHunter
Local dataset, no network
// Other services

Port 2976: CNS Server Port

Port 2976 is assigned by IANA to cns-srv-port (CNS Server Port).

2976

How cns-srv-port works

Other services
client:2976cns-srv-portresponse client:2976cns-srv-portresponse

The client sends a request to port 2976 and the cns-srv-port service answers.

Transport
TCP · 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)
Category
Other services
01 Security

Is port 2976 dangerous?

We have no specific security note for port 2976. 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 2976

ServicePortTransportDescriptionReferenceUpdated
cns-srv-port 2976 TCP, UDP CNS Server Port - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2976, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2976'      # process listening on 2976
sudo lsof -nP -i :2976

macOS

sudo lsof -nP -i :2976

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2976 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2976
netstat -ano | findstr :2976

From another machine

nmap -p 2976 -sV <host>
sudo nmap -sU -p 2976 <host>
nc -zv <host> 2976

Block it in the firewall

sudo ufw deny 2976/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2976" -Direction Inbound -LocalPort 2976 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2976 used for?

Port 2976 is assigned by IANA to cns-srv-port (CNS Server Port).

Is port 2976 TCP or UDP?

Port 2976 is registered for TCP and UDP.

Is it safe to open port 2976?

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 2976 is open?

On Linux run "ss -ltnup 'sport = :2976'", on macOS "lsof -nP -i :2976", and on Windows "netstat -ano | findstr :2976" to see the local process. From another machine, "nmap -p 2976 <host>" shows whether it is reachable.

05 Related
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