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Port 412 (synoptics-trap)

IANA assigns port 412 to synoptics-trap: Trap Convention Port.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
synoptics-trap TCP Trap Convention Port Illan Raab -
synoptics-trap UDP Trap Convention Port Illan Raab -

Check what is listening on port 412

Linux: is anything listening on TCP 412?
sudo ss -tlnp 'sport = :412'
Linux: UDP 412
sudo ss -ulnp 'sport = :412'
Linux / macOS: which process owns the port
sudo lsof -nP -i :412
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':412 '
Windows (Command Prompt)
netstat -ano | findstr :412
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 412 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 412
From Windows
Test-NetConnection HOST -Port 412
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 412

Block port 412 in the firewall

ufw
sudo ufw deny 412/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 412 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 412 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 412' -Direction Inbound -Protocol TCP -LocalPort 412 -Action Block
ufw
sudo ufw deny 412/udp
iptables
sudo iptables -A INPUT -p udp --dport 412 -j DROP
nftables
sudo nft add rule inet filter input udp dport 412 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 412' -Direction Inbound -Protocol UDP -LocalPort 412 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.