CyberHunter
Local dataset, no network
// Other services

Port 1331: intersan

Port 1331 is assigned by IANA to intersan (intersan).

1331

How intersan works

Other services
client:1331intersanresponse client:1331intersanresponse

The client sends a request to port 1331 and the intersan 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 1331 dangerous?

We have no specific security note for port 1331. 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 1331

ServicePortTransportDescriptionReferenceUpdated
intersan 1331 TCP, UDP intersan - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1331, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1331'      # process listening on 1331
sudo lsof -nP -i :1331

macOS

sudo lsof -nP -i :1331

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1331 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1331
netstat -ano | findstr :1331

From another machine

nmap -p 1331 -sV <host>
sudo nmap -sU -p 1331 <host>
nc -zv <host> 1331

Block it in the firewall

sudo ufw deny 1331/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1331" -Direction Inbound -LocalPort 1331 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1331 used for?

Port 1331 is assigned by IANA to intersan (intersan).

Is port 1331 TCP or UDP?

Port 1331 is registered for TCP and UDP.

Is it safe to open port 1331?

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 1331 is open?

On Linux run "ss -ltnup 'sport = :1331'", on macOS "lsof -nP -i :1331", and on Windows "netstat -ano | findstr :1331" to see the local process. From another machine, "nmap -p 1331 <host>" shows whether it is reachable.

05 Related
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