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Port 4103 (brlp-2)

IANA assigns port 4103 to brlp-2: Braille protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
brlp-2 TCP Braille protocol - -
brlp-2 UDP Braille protocol - -

Check what is listening on port 4103

Linux: is anything listening on TCP 4103?
sudo ss -tlnp 'sport = :4103'
Linux: UDP 4103
sudo ss -ulnp 'sport = :4103'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4103
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4103 '
Windows (Command Prompt)
netstat -ano | findstr :4103
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4103 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4103
From Windows
Test-NetConnection HOST -Port 4103
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4103

Block port 4103 in the firewall

ufw
sudo ufw deny 4103/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4103 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4103 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4103' -Direction Inbound -Protocol TCP -LocalPort 4103 -Action Block
ufw
sudo ufw deny 4103/udp
iptables
sudo iptables -A INPUT -p udp --dport 4103 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4103 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4103' -Direction Inbound -Protocol UDP -LocalPort 4103 -Action Block

Related ports

4101brlp-04102brlp-14104brlp-34105shofar

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