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// Other services

Port 6421: NIM_WAN

Port 6421 is assigned by IANA to nim-wan (NIM_WAN).

6421

How nim-wan works

Other services
client:6421nim-wanresponse client:6421nim-wanresponse

The client sends a request to port 6421 and the nim-wan 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 6421 dangerous?

We have no specific security note for port 6421. 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 6421

ServicePortTransportDescriptionReferenceUpdated
nim-wan 6421 TCP, UDP NIM_WAN - 2006-02

// source: IANA service name and port number registry

03 Check it

Which program uses port 6421, and is it reachable?

Linux

sudo ss -ltnup 'sport = :6421'      # process listening on 6421
sudo lsof -nP -i :6421

macOS

sudo lsof -nP -i :6421

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6421 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 6421
netstat -ano | findstr :6421

From another machine

nmap -p 6421 -sV <host>
sudo nmap -sU -p 6421 <host>
nc -zv <host> 6421

Block it in the firewall

sudo ufw deny 6421/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 6421" -Direction Inbound -LocalPort 6421 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 6421 used for?

Port 6421 is assigned by IANA to nim-wan (NIM_WAN).

Is port 6421 TCP or UDP?

Port 6421 is registered for TCP and UDP.

Is it safe to open port 6421?

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 6421 is open?

On Linux run "ss -ltnup 'sport = :6421'", on macOS "lsof -nP -i :6421", and on Windows "netstat -ano | findstr :6421" to see the local process. From another machine, "nmap -p 6421 <host>" shows whether it is reachable.

05 Related
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