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// Network services

Port 2164: Dynamic DNS Version 3

Port 2164 is assigned by IANA to ddns-v3 (Dynamic DNS Version 3).

2164

How ddns-v3 works

Network services
client:2164ddns-v3response client:2164ddns-v3response

The client sends a request to port 2164 and the ddns-v3 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
Network services
01 Security

Is port 2164 dangerous?

We have no specific security note for port 2164. Its risk depends on the program actually listening on it. General advice for network services services:

  • Answer only the networks that need the service (no open resolvers, relays or reflectors).
  • UDP services can be abused for DDoS amplification: rate-limit or block them at the edge.
  • Disable legacy test services that have no use in production.
02 Registry

IANA registry entries for port 2164

ServicePortTransportDescriptionReferenceUpdated
ddns-v3 2164 TCP, UDP Dynamic DNS Version 3 - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2164, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2164'      # process listening on 2164
sudo lsof -nP -i :2164

macOS

sudo lsof -nP -i :2164

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2164 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2164
netstat -ano | findstr :2164

From another machine

nmap -p 2164 -sV <host>
sudo nmap -sU -p 2164 <host>
nc -zv <host> 2164

Block it in the firewall

sudo ufw deny 2164/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2164" -Direction Inbound -LocalPort 2164 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2164 used for?

Port 2164 is assigned by IANA to ddns-v3 (Dynamic DNS Version 3).

Is port 2164 TCP or UDP?

Port 2164 is registered for TCP and UDP.

Is it safe to open port 2164?

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. Answer only the networks that need the service (no open resolvers, relays or reflectors).

How do I check if port 2164 is open?

On Linux run "ss -ltnup 'sport = :2164'", on macOS "lsof -nP -i :2164", and on Windows "netstat -ano | findstr :2164" to see the local process. From another machine, "nmap -p 2164 <host>" shows whether it is reachable.

05 Related
:53 DNS tcp · udp · moderate risk :135 MS RPC tcp · udp · high risk :123 NTP udp · tcp · moderate risk :67 DHCP server udp · tcp · moderate risk :111 rpcbind tcp · udp · high risk :9100 Raw printing (JetDirect) tcp · udp · high risk :631 IPP / CUPS tcp · udp · high risk :5353 mDNS udp · tcp · moderate risk

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