CyberHunter
LinkedIn profile - Bastien Cordier Email: contact@bastiencordier.pro
// Other services

Port 4785: Cisco Nexus Control Protocol

Port 4785 is assigned by IANA to cncp (Cisco Nexus Control Protocol).

4785

How cncp works

Other services
client:4785cncpresponse client:4785cncpresponse

The client sends a request to port 4785 and the cncp service answers.

Transport
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 4785 dangerous?

We have no specific security note for port 4785. 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 4785

ServicePortTransportDescriptionReferenceUpdated
cncp 4785 UDP Cisco Nexus Control Protocol - 2009-04-01
-4785-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 4785, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4785'      # process listening on 4785
sudo lsof -nP -i :4785

macOS

sudo lsof -nP -i :4785

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4785 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4785
netstat -ano | findstr :4785

From another machine

nmap -p 4785 -sV <host>
sudo nmap -sU -p 4785 <host>
nc -zv <host> 4785

Block it in the firewall

sudo ufw deny 4785/udp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4785" -Direction Inbound -LocalPort 4785 -Protocol UDP -Action Block  # Windows
04 FAQ
What is port 4785 used for?

Port 4785 is assigned by IANA to cncp (Cisco Nexus Control Protocol).

Is port 4785 TCP or UDP?

Port 4785 is registered for UDP.

Is it safe to open port 4785?

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 4785 is open?

On Linux run "ss -ltnup 'sport = :4785'", on macOS "lsof -nP -i :4785", and on Windows "netstat -ano | findstr :4785" to see the local process. From another machine, "nmap -p 4785 <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