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// Other services

Port 1735: PrivateChat

Port 1735 is assigned by IANA to privatechat (PrivateChat).

1735

How privatechat works

Other services
client:1735privatechatresponse client:1735privatechatresponse

The client sends a request to port 1735 and the privatechat 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 1735 dangerous?

We have no specific security note for port 1735. 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 1735

ServicePortTransportDescriptionReferenceUpdated
privatechat 1735 TCP, UDP PrivateChat - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1735, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1735'      # process listening on 1735
sudo lsof -nP -i :1735

macOS

sudo lsof -nP -i :1735

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1735 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1735
netstat -ano | findstr :1735

From another machine

nmap -p 1735 -sV <host>
sudo nmap -sU -p 1735 <host>
nc -zv <host> 1735

Block it in the firewall

sudo ufw deny 1735/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1735" -Direction Inbound -LocalPort 1735 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1735 used for?

Port 1735 is assigned by IANA to privatechat (PrivateChat).

Is port 1735 TCP or UDP?

Port 1735 is registered for TCP and UDP.

Is it safe to open port 1735?

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 1735 is open?

On Linux run "ss -ltnup 'sport = :1735'", on macOS "lsof -nP -i :1735", and on Windows "netstat -ano | findstr :1735" to see the local process. From another machine, "nmap -p 1735 <host>" shows whether it is reachable.

05 Related
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