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// Remote access

Port 2564: HP 3000 NS/VT block mode telnet

Port 2564 is assigned by IANA to hp-3000-telnet (HP 3000 NS/VT block mode telnet).

2564

How hp-3000-telnet works

Remote access
terminal:2564hp-3000-telnet terminal:2564hp-3000-telnet

The client opens a session to port 2564: each command typed is sent to the server, which runs it and returns the output.

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
Remote access
01 Security

Is port 2564 dangerous?

We have no specific security note for port 2564. Its risk depends on the program actually listening on it. General advice for remote access services:

  • Do not expose remote administration directly: use a VPN or a zero-trust access proxy.
  • Require MFA or key-based authentication and lock out brute-force attempts.
  • Log every login and alert on new source addresses.
02 Registry

IANA registry entries for port 2564

ServicePortTransportDescriptionReferenceUpdated
hp-3000-telnet 2564 TCP, UDP HP 3000 NS/VT block mode telnet - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2564, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2564'      # process listening on 2564
sudo lsof -nP -i :2564

macOS

sudo lsof -nP -i :2564

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2564 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2564
netstat -ano | findstr :2564

From another machine

nmap -p 2564 -sV <host>
sudo nmap -sU -p 2564 <host>
nc -zv <host> 2564

Block it in the firewall

sudo ufw deny 2564/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2564" -Direction Inbound -LocalPort 2564 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2564 used for?

Port 2564 is assigned by IANA to hp-3000-telnet (HP 3000 NS/VT block mode telnet).

Is port 2564 TCP or UDP?

Port 2564 is registered for TCP and UDP.

Is it safe to open port 2564?

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. Do not expose remote administration directly: use a VPN or a zero-trust access proxy.

How do I check if port 2564 is open?

On Linux run "ss -ltnup 'sport = :2564'", on macOS "lsof -nP -i :2564", and on Windows "netstat -ano | findstr :2564" to see the local process. From another machine, "nmap -p 2564 <host>" shows whether it is reachable.

05 Related
:22 SSH tcp · udp · sctp · moderate risk :3389 RDP tcp · udp · critical risk :23 Telnet tcp · udp · critical risk :5900 VNC tcp · udp · critical risk :5985 WinRM (HTTP) tcp · udp · high risk :5986 WinRM (HTTPS) tcp · udp · high risk :10000 Webmin tcp · udp · high risk :89 SU/MIT Telnet Gateway tcp · udp

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