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Port 392 (synotics-broker)

IANA assigns port 392 to synotics-broker: SynOptics Port Broker Port.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
synotics-broker TCP SynOptics Port Broker Port Illan Raab -
synotics-broker UDP SynOptics Port Broker Port Illan Raab -

Check what is listening on port 392

Linux: is anything listening on TCP 392?
sudo ss -tlnp 'sport = :392'
Linux: UDP 392
sudo ss -ulnp 'sport = :392'
Linux / macOS: which process owns the port
sudo lsof -nP -i :392
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':392 '
Windows (Command Prompt)
netstat -ano | findstr :392
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 392 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 392
From Windows
Test-NetConnection HOST -Port 392
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 392

Block port 392 in the firewall

ufw
sudo ufw deny 392/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 392 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 392 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 392' -Direction Inbound -Protocol TCP -LocalPort 392 -Action Block
ufw
sudo ufw deny 392/udp
iptables
sudo iptables -A INPUT -p udp --dport 392 -j DROP
nftables
sudo nft add rule inet filter input udp dport 392 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 392' -Direction Inbound -Protocol UDP -LocalPort 392 -Action Block

Related ports

390uis391synotics-relay393meta5394embl-ndt

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.