CyberHunter
Local dataset, no network
// Other services

Port 9875: Session Announcement v1

Port 9875 is assigned by IANA to sapv1 (Session Announcement v1).

9875

How sapv1 works

Other services
client:9875sapv1response client:9875sapv1response

The client sends a request to port 9875 and the sapv1 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)
01 Security

Is port 9875 dangerous?

We have no specific security note for port 9875. 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 9875

ServicePortTransportDescriptionReferenceUpdated
sapv1 9875 TCP, UDP Session Announcement v1 RFC 2974 -

// source: IANA service name and port number registry

03 Check it

Which program uses port 9875, and is it reachable?

Linux

sudo ss -ltnup 'sport = :9875'      # process listening on 9875
sudo lsof -nP -i :9875

macOS

sudo lsof -nP -i :9875

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9875 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 9875
netstat -ano | findstr :9875

From another machine

nmap -p 9875 -sV <host>
sudo nmap -sU -p 9875 <host>
nc -zv <host> 9875

Block it in the firewall

sudo ufw deny 9875/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 9875" -Direction Inbound -LocalPort 9875 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 9875 used for?

Port 9875 is assigned by IANA to sapv1 (Session Announcement v1).

Is port 9875 TCP or UDP?

Port 9875 is registered for TCP and UDP.

Is it safe to open port 9875?

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 9875 is open?

On Linux run "ss -ltnup 'sport = :9875'", on macOS "lsof -nP -i :9875", and on Windows "netstat -ano | findstr :9875" to see the local process. From another machine, "nmap -p 9875 <host>" shows whether it is reachable.

05 Related

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