HTTPfy

Port 3104 (autocuelog, autocuetime)

IANA assigns port 3104 to autocuelog, autocuetime: Autocue Logger Protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
autocuelog TCP Autocue Logger Protocol - -
autocuetime UDP Autocue Time Service Geoff Back -

Check what is listening on port 3104

Linux: is anything listening on TCP 3104?
sudo ss -tlnp 'sport = :3104'
Linux: UDP 3104
sudo ss -ulnp 'sport = :3104'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3104
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3104 '
Windows (Command Prompt)
netstat -ano | findstr :3104
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3104 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3104
From Windows
Test-NetConnection HOST -Port 3104
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3104

Block port 3104 in the firewall

ufw
sudo ufw deny 3104/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3104 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3104 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3104' -Direction Inbound -Protocol TCP -LocalPort 3104 -Action Block
ufw
sudo ufw deny 3104/udp
iptables
sudo iptables -A INPUT -p udp --dport 3104 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3104 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3104' -Direction Inbound -Protocol UDP -LocalPort 3104 -Action Block

Related ports

3102slslavemon3103autocuesmi3105cardbox3106cardbox-http

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