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Port 16311 (pdefmns)

IANA assigns port 16311 to pdefmns: Policy definition and update management.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
pdefmns TCP Policy definition and update management Diane I Shannon -
pdefmns UDP Policy definition and update management Diane I Shannon -

Registry dates for this port: registered 2007-04.

Check what is listening on port 16311

Linux: is anything listening on TCP 16311?
sudo ss -tlnp 'sport = :16311'
Linux: UDP 16311
sudo ss -ulnp 'sport = :16311'
Linux / macOS: which process owns the port
sudo lsof -nP -i :16311
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':16311 '
Windows (Command Prompt)
netstat -ano | findstr :16311
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 16311 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 16311
From Windows
Test-NetConnection HOST -Port 16311
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 16311

Block port 16311 in the firewall

ufw
sudo ufw deny 16311/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 16311 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 16311 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 16311' -Direction Inbound -Protocol TCP -LocalPort 16311 -Action Block
ufw
sudo ufw deny 16311/udp
iptables
sudo iptables -A INPUT -p udp --dport 16311 -j DROP
nftables
sudo nft add rule inet filter input udp dport 16311 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 16311' -Direction Inbound -Protocol UDP -LocalPort 16311 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.