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// Other services

Port 13721: BPDBM Protocol (VERITAS NetBackup)

Port 13721 is assigned by IANA to bpdbm (BPDBM Protocol (VERITAS NetBackup)).

13721

How bpdbm works

Other services
client:13721bpdbmresponse client:13721bpdbmresponse

The client sends a request to port 13721 and the bpdbm 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 13721 dangerous?

We have no specific security note for port 13721. 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 13721

ServicePortTransportDescriptionReferenceUpdated
bpdbm 13721 TCP, UDP BPDBM Protocol (VERITAS NetBackup) - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 13721, and is it reachable?

Linux

sudo ss -ltnup 'sport = :13721'      # process listening on 13721
sudo lsof -nP -i :13721

macOS

sudo lsof -nP -i :13721

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 13721 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 13721
netstat -ano | findstr :13721

From another machine

nmap -p 13721 -sV <host>
sudo nmap -sU -p 13721 <host>
nc -zv <host> 13721

Block it in the firewall

sudo ufw deny 13721/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 13721" -Direction Inbound -LocalPort 13721 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 13721 used for?

Port 13721 is assigned by IANA to bpdbm (BPDBM Protocol (VERITAS NetBackup)).

Is port 13721 TCP or UDP?

Port 13721 is registered for TCP and UDP.

Is it safe to open port 13721?

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 13721 is open?

On Linux run "ss -ltnup 'sport = :13721'", on macOS "lsof -nP -i :13721", and on Windows "netstat -ano | findstr :13721" to see the local process. From another machine, "nmap -p 13721 <host>" shows whether it is reachable.

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