CyberHunter
Local dataset, no network
// Other services

Port 309: EntrustTime

Port 309 is assigned by IANA to entrusttime (EntrustTime).

309

How entrusttime works

Other services
client:309entrusttimeresponse client:309entrusttimeresponse

The client sends a request to port 309 and the entrusttime 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
Well-known (0-1023)
Category
Other services
01 Security

Is port 309 dangerous?

We have no specific security note for port 309. 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 309

ServicePortTransportDescriptionReferenceUpdated
entrusttime 309 TCP, UDP EntrustTime - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 309, and is it reachable?

Linux

sudo ss -ltnup 'sport = :309'      # process listening on 309
sudo lsof -nP -i :309

macOS

sudo lsof -nP -i :309

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 309 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 309
netstat -ano | findstr :309

From another machine

nmap -p 309 -sV <host>
sudo nmap -sU -p 309 <host>
nc -zv <host> 309

Block it in the firewall

sudo ufw deny 309/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 309" -Direction Inbound -LocalPort 309 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 309 used for?

Port 309 is assigned by IANA to entrusttime (EntrustTime).

Is port 309 TCP or UDP?

Port 309 is registered for TCP and UDP.

Is it safe to open port 309?

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 309 is open?

On Linux run "ss -ltnup 'sport = :309'", on macOS "lsof -nP -i :309", and on Windows "netstat -ano | findstr :309" to see the local process. From another machine, "nmap -p 309 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

Latest vulnerability news

All news