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// Network services

Port 444: Simple Network Paging Protocol

Port 444 is assigned by IANA to snpp (Simple Network Paging Protocol).

444

How snpp works

Network services
client:444snppresponse client:444snppresponse

The client sends a request to port 444 and the snpp 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
Network services
01 Security

Is port 444 dangerous?

We have no specific security note for port 444. 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 444

ServicePortTransportDescriptionReferenceUpdated
snpp 444 TCP, UDP Simple Network Paging Protocol RFC 1568 -

// source: IANA service name and port number registry

03 Check it

Which program uses port 444, and is it reachable?

Linux

sudo ss -ltnup 'sport = :444'      # process listening on 444
sudo lsof -nP -i :444

macOS

sudo lsof -nP -i :444

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 444 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 444
netstat -ano | findstr :444

From another machine

nmap -p 444 -sV <host>
sudo nmap -sU -p 444 <host>
nc -zv <host> 444

Block it in the firewall

sudo ufw deny 444/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 444" -Direction Inbound -LocalPort 444 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 444 used for?

Port 444 is assigned by IANA to snpp (Simple Network Paging Protocol).

Is port 444 TCP or UDP?

Port 444 is registered for TCP and UDP.

Is it safe to open port 444?

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 444 is open?

On Linux run "ss -ltnup 'sport = :444'", on macOS "lsof -nP -i :444", and on Windows "netstat -ano | findstr :444" to see the local process. From another machine, "nmap -p 444 <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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