CyberHunter
Local dataset, no network
// Other services

Port 751:

Port 751 is assigned by IANA to pump ().

751

How pump works

Other services
client:751pumpresponse client:751pumpresponse

The client sends a request to port 751 and the pump 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 751 dangerous?

We have no specific security note for port 751. 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 751

ServicePortTransportDescriptionReferenceUpdated
pump 751 TCP, UDP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 751, and is it reachable?

Linux

sudo ss -ltnup 'sport = :751'      # process listening on 751
sudo lsof -nP -i :751

macOS

sudo lsof -nP -i :751

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 751 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 751
netstat -ano | findstr :751

From another machine

nmap -p 751 -sV <host>
sudo nmap -sU -p 751 <host>
nc -zv <host> 751

Block it in the firewall

sudo ufw deny 751/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 751" -Direction Inbound -LocalPort 751 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 751 used for?

Port 751 is assigned by IANA to pump ().

Is port 751 TCP or UDP?

Port 751 is registered for TCP and UDP.

Is it safe to open port 751?

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 751 is open?

On Linux run "ss -ltnup 'sport = :751'", on macOS "lsof -nP -i :751", and on Windows "netstat -ano | findstr :751" to see the local process. From another machine, "nmap -p 751 <host>" shows whether it is reachable.

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