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Port 4351 (plcy-net-svcs)

IANA assigns port 4351 to plcy-net-svcs: PLCY Net Services.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
plcy-net-svcs TCP PLCY Net Services J J Ekstrom -
plcy-net-svcs UDP PLCY Net Services J J Ekstrom -

Check what is listening on port 4351

Linux: is anything listening on TCP 4351?
sudo ss -tlnp 'sport = :4351'
Linux: UDP 4351
sudo ss -ulnp 'sport = :4351'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4351
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4351 '
Windows (Command Prompt)
netstat -ano | findstr :4351
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4351 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4351
From Windows
Test-NetConnection HOST -Port 4351
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4351

Block port 4351 in the firewall

ufw
sudo ufw deny 4351/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4351 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4351 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4351' -Direction Inbound -Protocol TCP -LocalPort 4351 -Action Block
ufw
sudo ufw deny 4351/udp
iptables
sudo iptables -A INPUT -p udp --dport 4351 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4351 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4351' -Direction Inbound -Protocol UDP -LocalPort 4351 -Action Block

Related ports

4349fsportmap4350net-device4352pjlink4353f5-iquery

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