CyberHunter
// Other services

Port 596: SMSD

Port 596 is assigned by IANA to smsd (SMSD).

596

How smsd works

Other services
client:596smsdresponse client:596smsdresponse

The client sends a request to port 596 and the smsd 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)
01 Security

Is port 596 dangerous?

We have no specific security note for port 596. 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 596

ServicePortTransportDescriptionReferenceUpdated
smsd 596 TCP, UDP SMSD - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 596, and is it reachable?

Linux

sudo ss -ltnup 'sport = :596'      # process listening on 596
sudo lsof -nP -i :596

macOS

sudo lsof -nP -i :596

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 596 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 596
netstat -ano | findstr :596

From another machine

nmap -p 596 -sV <host>
sudo nmap -sU -p 596 <host>
nc -zv <host> 596

Block it in the firewall

sudo ufw deny 596/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 596" -Direction Inbound -LocalPort 596 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 596 used for?

Port 596 is assigned by IANA to smsd (SMSD).

Is port 596 TCP or UDP?

Port 596 is registered for TCP and UDP.

Is it safe to open port 596?

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 596 is open?

On Linux run "ss -ltnup 'sport = :596'", on macOS "lsof -nP -i :596", and on Windows "netstat -ano | findstr :596" to see the local process. From another machine, "nmap -p 596 <host>" shows whether it is reachable.

05 Related