- 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.
Port 16789: This server provides callable services to mainframe External Security Managers from any TCP/IP platform
Port 16789 is assigned by IANA to cadsisvr (This server provides callable services to mainframe External Security Managers from any TCP/IP platform).
16789
How cadsisvr works
Other servicesThe client sends a request to port 16789 and the cadsisvr service answers.
- Transport
- TCP
- 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
Is port 16789 dangerous?
We have no specific security note for port 16789. Its risk depends on the program actually listening on it. General advice for other services services:
IANA registry entries for port 16789
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| cadsisvr | 16789 | TCP | This server provides callable services to mainframe External Security Managers from any TCP/IP platform | - | 2023-03-29 |
| - | 16789 | - | Reserved | - | - |
// source: IANA service name and port number registry
Which program uses port 16789, and is it reachable?
Linux
sudo ss -ltnup 'sport = :16789' # process listening on 16789
sudo lsof -nP -i :16789macOS
sudo lsof -nP -i :16789
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 16789 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 16789 netstat -ano | findstr :16789
From another machine
nmap -p 16789 -sV <host> nc -zv <host> 16789
Block it in the firewall
sudo ufw deny 16789/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 16789" -Direction Inbound -LocalPort 16789 -Protocol TCP -Action Block # Windows
What is port 16789 used for?
Port 16789 is assigned by IANA to cadsisvr (This server provides callable services to mainframe External Security Managers from any TCP/IP platform).
Is port 16789 TCP or UDP?
Port 16789 is registered for TCP.
Is it safe to open port 16789?
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 16789 is open?
On Linux run "ss -ltnup 'sport = :16789'", on macOS "lsof -nP -i :16789", and on Windows "netstat -ano | findstr :16789" to see the local process. From another machine, "nmap -p 16789 <host>" shows whether it is reachable.
Other other services ports
: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