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// Other services

Port 3400: CSMS2

Port 3400 is assigned by IANA to csms2 (CSMS2).

3400

How csms2 works

Other services
client:3400csms2response client:3400csms2response

The client sends a request to port 3400 and the csms2 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 3400 dangerous?

We have no specific security note for port 3400. 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 3400

ServicePortTransportDescriptionReferenceUpdated
csms2 3400 TCP, UDP CSMS2 - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 3400, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3400'      # process listening on 3400
sudo lsof -nP -i :3400

macOS

sudo lsof -nP -i :3400

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3400 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3400
netstat -ano | findstr :3400

From another machine

nmap -p 3400 -sV <host>
sudo nmap -sU -p 3400 <host>
nc -zv <host> 3400

Block it in the firewall

sudo ufw deny 3400/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3400" -Direction Inbound -LocalPort 3400 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3400 used for?

Port 3400 is assigned by IANA to csms2 (CSMS2).

Is port 3400 TCP or UDP?

Port 3400 is registered for TCP and UDP.

Is it safe to open port 3400?

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 3400 is open?

On Linux run "ss -ltnup 'sport = :3400'", on macOS "lsof -nP -i :3400", and on Windows "netstat -ano | findstr :3400" to see the local process. From another machine, "nmap -p 3400 <host>" shows whether it is reachable.

05 Related
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