HTTPfy

Port 4104 (brlp-3)

IANA assigns port 4104 to brlp-3: Braille protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
brlp-3 TCP Braille protocol Sebastien Hinderer -
brlp-3 UDP Braille protocol Sebastien Hinderer -

Registry dates for this port: registered 2006-03.

Check what is listening on port 4104

Linux: is anything listening on TCP 4104?
sudo ss -tlnp 'sport = :4104'
Linux: UDP 4104
sudo ss -ulnp 'sport = :4104'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4104
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4104 '
Windows (Command Prompt)
netstat -ano | findstr :4104
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4104 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4104
From Windows
Test-NetConnection HOST -Port 4104
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4104

Block port 4104 in the firewall

ufw
sudo ufw deny 4104/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4104 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4104 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4104' -Direction Inbound -Protocol TCP -LocalPort 4104 -Action Block
ufw
sudo ufw deny 4104/udp
iptables
sudo iptables -A INPUT -p udp --dport 4104 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4104 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4104' -Direction Inbound -Protocol UDP -LocalPort 4104 -Action Block

Related ports

4102brlp-14103brlp-24105shofar4106synchronite

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