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Port 5354 (mdnsresponder)

IANA assigns port 5354 to mdnsresponder: Multicast DNS Responder IPC.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
mdnsresponder TCP Multicast DNS Responder IPC Stuart Cheshire 3 -
mdnsresponder UDP Multicast DNS Responder IPC Stuart Cheshire 3 -

Registry dates for this port: registered 2004-06.

Check what is listening on port 5354

Linux: is anything listening on TCP 5354?
sudo ss -tlnp 'sport = :5354'
Linux: UDP 5354
sudo ss -ulnp 'sport = :5354'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5354
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5354 '
Windows (Command Prompt)
netstat -ano | findstr :5354
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5354 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5354
From Windows
Test-NetConnection HOST -Port 5354
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5354

Block port 5354 in the firewall

ufw
sudo ufw deny 5354/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5354 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5354 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5354' -Direction Inbound -Protocol TCP -LocalPort 5354 -Action Block
ufw
sudo ufw deny 5354/udp
iptables
sudo iptables -A INPUT -p udp --dport 5354 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5354 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5354' -Direction Inbound -Protocol UDP -LocalPort 5354 -Action Block

Related ports

5352dns-llq5353mDNS (Bonjour)5355LLMNR5356ms-smlbiz

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