CyberHunter
Local dataset, no network
// Other services

Port 8891: Desktop Data TCP 3: NESS application

Port 8891 is assigned by IANA to ddi-tcp-4 (Desktop Data TCP 3: NESS application), ddi-udp-4 (Desktop Data UDP 3: NESS application).

8891

How ddi-tcp-4 works

Other services
client:8891ddi-tcp-4response client:8891ddi-tcp-4response

The client sends a request to port 8891 and the ddi-tcp-4 service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned2 registered services
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 8891 dangerous?

We have no specific security note for port 8891. 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 8891

ServicePortTransportDescriptionReferenceUpdated
ddi-tcp-4 8891 TCP Desktop Data TCP 3: NESS application - -
ddi-udp-4 8891 UDP Desktop Data UDP 3: NESS application - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 8891, and is it reachable?

Linux

sudo ss -ltnup 'sport = :8891'      # process listening on 8891
sudo lsof -nP -i :8891

macOS

sudo lsof -nP -i :8891

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 8891 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 8891
netstat -ano | findstr :8891

From another machine

nmap -p 8891 -sV <host>
sudo nmap -sU -p 8891 <host>
nc -zv <host> 8891

Block it in the firewall

sudo ufw deny 8891/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 8891" -Direction Inbound -LocalPort 8891 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 8891 used for?

Port 8891 is assigned by IANA to ddi-tcp-4 (Desktop Data TCP 3: NESS application), ddi-udp-4 (Desktop Data UDP 3: NESS application).

Is port 8891 TCP or UDP?

Port 8891 is registered for TCP and UDP.

Is it safe to open port 8891?

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 8891 is open?

On Linux run "ss -ltnup 'sport = :8891'", on macOS "lsof -nP -i :8891", and on Windows "netstat -ano | findstr :8891" to see the local process. From another machine, "nmap -p 8891 <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

Latest vulnerability news

All news