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Port 3437 (autocueds)

IANA assigns port 3437 to autocueds: Autocue Directory Service.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
autocueds TCP Autocue Directory Service Geoff Back -
autocueds UDP Autocue Directory Service Geoff Back -

Registry dates for this port: registered 2002-03.

Check what is listening on port 3437

Linux: is anything listening on TCP 3437?
sudo ss -tlnp 'sport = :3437'
Linux: UDP 3437
sudo ss -ulnp 'sport = :3437'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3437
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3437 '
Windows (Command Prompt)
netstat -ano | findstr :3437
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3437 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3437
From Windows
Test-NetConnection HOST -Port 3437
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3437

Block port 3437 in the firewall

ufw
sudo ufw deny 3437/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3437 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3437 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3437' -Direction Inbound -Protocol TCP -LocalPort 3437 -Action Block
ufw
sudo ufw deny 3437/udp
iptables
sudo iptables -A INPUT -p udp --dport 3437 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3437 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3437' -Direction Inbound -Protocol UDP -LocalPort 3437 -Action Block

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3435pacom3436gc-config3438spiral-admin3439hri-port

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