CyberHunter
Local dataset, no network
// Other services

Port 535: iiop

Port 535 is assigned by IANA to iiop (iiop).

535

How iiop works

Other services
client:535iiopresponse client:535iiopresponse

The client sends a request to port 535 and the iiop 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 535 dangerous?

We have no specific security note for port 535. 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 535

ServicePortTransportDescriptionReferenceUpdated
iiop 535 TCP, UDP iiop - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 535, and is it reachable?

Linux

sudo ss -ltnup 'sport = :535'      # process listening on 535
sudo lsof -nP -i :535

macOS

sudo lsof -nP -i :535

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 535 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 535
netstat -ano | findstr :535

From another machine

nmap -p 535 -sV <host>
sudo nmap -sU -p 535 <host>
nc -zv <host> 535

Block it in the firewall

sudo ufw deny 535/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 535" -Direction Inbound -LocalPort 535 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 535 used for?

Port 535 is assigned by IANA to iiop (iiop).

Is port 535 TCP or UDP?

Port 535 is registered for TCP and UDP.

Is it safe to open port 535?

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 535 is open?

On Linux run "ss -ltnup 'sport = :535'", on macOS "lsof -nP -i :535", and on Windows "netstat -ano | findstr :535" to see the local process. From another machine, "nmap -p 535 <host>" shows whether it is reachable.

05 Related
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