CyberHunter
Local dataset, no network
// Other services

Port 1850: GSI

Port 1850 is assigned by IANA to gsi (GSI).

1850

How gsi works

Other services
client:1850gsiresponse client:1850gsiresponse

The client sends a request to port 1850 and the gsi 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 1850 dangerous?

We have no specific security note for port 1850. 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 1850

ServicePortTransportDescriptionReferenceUpdated
gsi 1850 TCP, UDP GSI - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1850, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1850'      # process listening on 1850
sudo lsof -nP -i :1850

macOS

sudo lsof -nP -i :1850

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1850 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1850
netstat -ano | findstr :1850

From another machine

nmap -p 1850 -sV <host>
sudo nmap -sU -p 1850 <host>
nc -zv <host> 1850

Block it in the firewall

sudo ufw deny 1850/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1850" -Direction Inbound -LocalPort 1850 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1850 used for?

Port 1850 is assigned by IANA to gsi (GSI).

Is port 1850 TCP or UDP?

Port 1850 is registered for TCP and UDP.

Is it safe to open port 1850?

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 1850 is open?

On Linux run "ss -ltnup 'sport = :1850'", on macOS "lsof -nP -i :1850", and on Windows "netstat -ano | findstr :1850" to see the local process. From another machine, "nmap -p 1850 <host>" shows whether it is reachable.

05 Related
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