- 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.
Port 4394: American Printware Discovery
Port 4394 is assigned by IANA to apwi-disc (American Printware Discovery).
4394
How apwi-disc works
Network servicesThe client sends a request to port 4394 and the apwi-disc service answers.
- Transport
- 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
Is port 4394 dangerous?
We have no specific security note for port 4394. Its risk depends on the program actually listening on it. General advice for network services services:
IANA registry entries for port 4394
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| apwi-disc | 4394 | UDP | American Printware Discovery | - | 2009-02-12 |
| - | 4394 | - | Reserved | - | - |
// source: IANA service name and port number registry
Which program uses port 4394, and is it reachable?
Linux
sudo ss -ltnup 'sport = :4394' # process listening on 4394
sudo lsof -nP -i :4394macOS
sudo lsof -nP -i :4394
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4394 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 4394 netstat -ano | findstr :4394
From another machine
nmap -p 4394 -sV <host> sudo nmap -sU -p 4394 <host> nc -zv <host> 4394
Block it in the firewall
sudo ufw deny 4394/udp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 4394" -Direction Inbound -LocalPort 4394 -Protocol UDP -Action Block # Windows
What is port 4394 used for?
Port 4394 is assigned by IANA to apwi-disc (American Printware Discovery).
Is port 4394 TCP or UDP?
Port 4394 is registered for UDP.
Is it safe to open port 4394?
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 4394 is open?
On Linux run "ss -ltnup 'sport = :4394'", on macOS "lsof -nP -i :4394", and on Windows "netstat -ano | findstr :4394" to see the local process. From another machine, "nmap -p 4394 <host>" shows whether it is reachable.
Other network services ports
: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