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// Other services

Port 9911: SYPECom Transport Protocol

Port 9911 is assigned by IANA to sype-transport (SYPECom Transport Protocol).

9911

How sype-transport works

Other services
client:9911sype-transportresponse client:9911sype-transportresponse

The client sends a request to port 9911 and the sype-transport 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 9911 dangerous?

We have no specific security note for port 9911. 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 9911

ServicePortTransportDescriptionReferenceUpdated
sype-transport 9911 TCP, UDP SYPECom Transport Protocol - 2003-03

// source: IANA service name and port number registry

03 Check it

Which program uses port 9911, and is it reachable?

Linux

sudo ss -ltnup 'sport = :9911'      # process listening on 9911
sudo lsof -nP -i :9911

macOS

sudo lsof -nP -i :9911

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9911 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 9911
netstat -ano | findstr :9911

From another machine

nmap -p 9911 -sV <host>
sudo nmap -sU -p 9911 <host>
nc -zv <host> 9911

Block it in the firewall

sudo ufw deny 9911/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 9911" -Direction Inbound -LocalPort 9911 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 9911 used for?

Port 9911 is assigned by IANA to sype-transport (SYPECom Transport Protocol).

Is port 9911 TCP or UDP?

Port 9911 is registered for TCP and UDP.

Is it safe to open port 9911?

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 9911 is open?

On Linux run "ss -ltnup 'sport = :9911'", on macOS "lsof -nP -i :9911", and on Windows "netstat -ano | findstr :9911" to see the local process. From another machine, "nmap -p 9911 <host>" shows whether it is reachable.

05 Related
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