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Port 3514 (must-p2p)

IANA assigns port 3514 to must-p2p: MUST Peer to Peer.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
must-p2p TCP MUST Peer to Peer - -
must-p2p UDP MUST Peer to Peer - -

Check what is listening on port 3514

Linux: is anything listening on TCP 3514?
sudo ss -tlnp 'sport = :3514'
Linux: UDP 3514
sudo ss -ulnp 'sport = :3514'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3514
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3514 '
Windows (Command Prompt)
netstat -ano | findstr :3514
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3514 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3514
From Windows
Test-NetConnection HOST -Port 3514
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3514

Block port 3514 in the firewall

ufw
sudo ufw deny 3514/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3514 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3514 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3514' -Direction Inbound -Protocol TCP -LocalPort 3514 -Action Block
ufw
sudo ufw deny 3514/udp
iptables
sudo iptables -A INPUT -p udp --dport 3514 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3514 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3514' -Direction Inbound -Protocol UDP -LocalPort 3514 -Action Block

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