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Port 28000 (nxlmd)

IANA assigns port 28000 to nxlmd: NX License Manager.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
nxlmd TCP NX License Manager Anthony Greatorex -
nxlmd UDP NX License Manager Anthony Greatorex -

Registry dates for this port: registered 2004-11.

Check what is listening on port 28000

Linux: is anything listening on TCP 28000?
sudo ss -tlnp 'sport = :28000'
Linux: UDP 28000
sudo ss -ulnp 'sport = :28000'
Linux / macOS: which process owns the port
sudo lsof -nP -i :28000
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':28000 '
Windows (Command Prompt)
netstat -ano | findstr :28000
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 28000 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 28000
From Windows
Test-NetConnection HOST -Port 28000
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 28000

Block port 28000 in the firewall

ufw
sudo ufw deny 28000/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 28000 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 28000 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 28000' -Direction Inbound -Protocol TCP -LocalPort 28000 -Action Block
ufw
sudo ufw deny 28000/udp
iptables
sudo iptables -A INPUT -p udp --dport 28000 -j DROP
nftables
sudo nft add rule inet filter input udp dport 28000 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 28000' -Direction Inbound -Protocol UDP -LocalPort 28000 -Action Block

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