CyberHunter
Local dataset, no network
// Other services

Port 1817: RKB-OSCS

Port 1817 is assigned by IANA to rkb-oscs (RKB-OSCS).

1817

How rkb-oscs works

Other services
client:1817rkb-oscsresponse client:1817rkb-oscsresponse

The client sends a request to port 1817 and the rkb-oscs 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 1817 dangerous?

We have no specific security note for port 1817. 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 1817

ServicePortTransportDescriptionReferenceUpdated
rkb-oscs 1817 TCP, UDP RKB-OSCS - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1817, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1817'      # process listening on 1817
sudo lsof -nP -i :1817

macOS

sudo lsof -nP -i :1817

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1817 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1817
netstat -ano | findstr :1817

From another machine

nmap -p 1817 -sV <host>
sudo nmap -sU -p 1817 <host>
nc -zv <host> 1817

Block it in the firewall

sudo ufw deny 1817/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1817" -Direction Inbound -LocalPort 1817 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1817 used for?

Port 1817 is assigned by IANA to rkb-oscs (RKB-OSCS).

Is port 1817 TCP or UDP?

Port 1817 is registered for TCP and UDP.

Is it safe to open port 1817?

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 1817 is open?

On Linux run "ss -ltnup 'sport = :1817'", on macOS "lsof -nP -i :1817", and on Windows "netstat -ano | findstr :1817" to see the local process. From another machine, "nmap -p 1817 <host>" shows whether it is reachable.

05 Related
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