- 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 404: nced
Port 404 is assigned by IANA to nced (nced).
404
How nced works
Other servicesThe client sends a request to port 404 and the nced 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
- Well-known (0-1023)
- Category
- Other services
Is port 404 dangerous?
We have no specific security note for port 404. Its risk depends on the program actually listening on it. General advice for other services services:
IANA registry entries for port 404
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| nced | 404 | TCP, UDP | nced | - | - |
// source: IANA service name and port number registry
Which program uses port 404, and is it reachable?
Linux
sudo ss -ltnup 'sport = :404' # process listening on 404
sudo lsof -nP -i :404macOS
sudo lsof -nP -i :404
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 404 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 404 netstat -ano | findstr :404
From another machine
nmap -p 404 -sV <host> sudo nmap -sU -p 404 <host> nc -zv <host> 404
Block it in the firewall
sudo ufw deny 404/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 404" -Direction Inbound -LocalPort 404 -Protocol TCP -Action Block # Windows
What is port 404 used for?
Port 404 is assigned by IANA to nced (nced).
Is port 404 TCP or UDP?
Port 404 is registered for TCP and UDP.
Is it safe to open port 404?
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 404 is open?
On Linux run "ss -ltnup 'sport = :404'", on macOS "lsof -nP -i :404", and on Windows "netstat -ano | findstr :404" to see the local process. From another machine, "nmap -p 404 <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