CyberHunter
Local dataset, no network
// Other services

Port 1687: nsjtp-ctrl

Port 1687 is assigned by IANA to nsjtp-ctrl (nsjtp-ctrl).

1687

How nsjtp-ctrl works

Other services
client:1687nsjtp-ctrlresponse client:1687nsjtp-ctrlresponse

The client sends a request to port 1687 and the nsjtp-ctrl 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)
01 Security

Is port 1687 dangerous?

We have no specific security note for port 1687. 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 1687

ServicePortTransportDescriptionReferenceUpdated
nsjtp-ctrl 1687 TCP, UDP nsjtp-ctrl - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1687, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1687'      # process listening on 1687
sudo lsof -nP -i :1687

macOS

sudo lsof -nP -i :1687

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1687 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1687
netstat -ano | findstr :1687

From another machine

nmap -p 1687 -sV <host>
sudo nmap -sU -p 1687 <host>
nc -zv <host> 1687

Block it in the firewall

sudo ufw deny 1687/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1687" -Direction Inbound -LocalPort 1687 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1687 used for?

Port 1687 is assigned by IANA to nsjtp-ctrl (nsjtp-ctrl).

Is port 1687 TCP or UDP?

Port 1687 is registered for TCP and UDP.

Is it safe to open port 1687?

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 1687 is open?

On Linux run "ss -ltnup 'sport = :1687'", on macOS "lsof -nP -i :1687", and on Windows "netstat -ano | findstr :1687" to see the local process. From another machine, "nmap -p 1687 <host>" shows whether it is reachable.

05 Related

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