CyberHunter
Local dataset, no network
// Other services

Port 763:

Port 763 is assigned by IANA to cycleserv ().

763

How cycleserv works

Other services
client:763cycleservresponse client:763cycleservresponse

The client sends a request to port 763 and the cycleserv 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 763 dangerous?

We have no specific security note for port 763. 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 763

ServicePortTransportDescriptionReferenceUpdated
cycleserv 763 TCP, UDP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 763, and is it reachable?

Linux

sudo ss -ltnup 'sport = :763'      # process listening on 763
sudo lsof -nP -i :763

macOS

sudo lsof -nP -i :763

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 763 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 763
netstat -ano | findstr :763

From another machine

nmap -p 763 -sV <host>
sudo nmap -sU -p 763 <host>
nc -zv <host> 763

Block it in the firewall

sudo ufw deny 763/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 763" -Direction Inbound -LocalPort 763 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 763 used for?

Port 763 is assigned by IANA to cycleserv ().

Is port 763 TCP or UDP?

Port 763 is registered for TCP and UDP.

Is it safe to open port 763?

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 763 is open?

On Linux run "ss -ltnup 'sport = :763'", on macOS "lsof -nP -i :763", and on Windows "netstat -ano | findstr :763" to see the local process. From another machine, "nmap -p 763 <host>" shows whether it is reachable.

05 Related
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