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// Other services

Port 16991: INTEL-RCI-MP

Port 16991 is assigned by IANA to intel-rci-mp (INTEL-RCI-MP).

16991

How intel-rci-mp works

Other services
client:16991intel-rci-mpresponse client:16991intel-rci-mpresponse

The client sends a request to port 16991 and the intel-rci-mp 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 16991 dangerous?

We have no specific security note for port 16991. 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 16991

ServicePortTransportDescriptionReferenceUpdated
intel-rci-mp 16991 TCP, UDP INTEL-RCI-MP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 16991, and is it reachable?

Linux

sudo ss -ltnup 'sport = :16991'      # process listening on 16991
sudo lsof -nP -i :16991

macOS

sudo lsof -nP -i :16991

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 16991 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 16991
netstat -ano | findstr :16991

From another machine

nmap -p 16991 -sV <host>
sudo nmap -sU -p 16991 <host>
nc -zv <host> 16991

Block it in the firewall

sudo ufw deny 16991/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 16991" -Direction Inbound -LocalPort 16991 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 16991 used for?

Port 16991 is assigned by IANA to intel-rci-mp (INTEL-RCI-MP).

Is port 16991 TCP or UDP?

Port 16991 is registered for TCP and UDP.

Is it safe to open port 16991?

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 16991 is open?

On Linux run "ss -ltnup 'sport = :16991'", on macOS "lsof -nP -i :16991", and on Windows "netstat -ano | findstr :16991" to see the local process. From another machine, "nmap -p 16991 <host>" shows whether it is reachable.

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