CyberHunter
Local dataset, no network
// Other services

Port 1688: nsjtp-data

Port 1688 is assigned by IANA to nsjtp-data (nsjtp-data).

1688

How nsjtp-data works

Other services
client:1688nsjtp-dataresponse client:1688nsjtp-dataresponse

The client sends a request to port 1688 and the nsjtp-data 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 1688 dangerous?

We have no specific security note for port 1688. 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 1688

ServicePortTransportDescriptionReferenceUpdated
nsjtp-data 1688 TCP, UDP nsjtp-data - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1688, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1688'      # process listening on 1688
sudo lsof -nP -i :1688

macOS

sudo lsof -nP -i :1688

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1688 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1688
netstat -ano | findstr :1688

From another machine

nmap -p 1688 -sV <host>
sudo nmap -sU -p 1688 <host>
nc -zv <host> 1688

Block it in the firewall

sudo ufw deny 1688/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1688" -Direction Inbound -LocalPort 1688 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1688 used for?

Port 1688 is assigned by IANA to nsjtp-data (nsjtp-data).

Is port 1688 TCP or UDP?

Port 1688 is registered for TCP and UDP.

Is it safe to open port 1688?

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 1688 is open?

On Linux run "ss -ltnup 'sport = :1688'", on macOS "lsof -nP -i :1688", and on Windows "netstat -ano | findstr :1688" to see the local process. From another machine, "nmap -p 1688 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

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