HTTPfy

Port 21554 (dfserver)

IANA assigns port 21554 to dfserver: MineScape Design File Server.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
dfserver TCP MineScape Design File Server Michael Purser -
dfserver UDP MineScape Design File Server Michael Purser -

Registry dates for this port: registered 2006-06.

Check what is listening on port 21554

Linux: is anything listening on TCP 21554?
sudo ss -tlnp 'sport = :21554'
Linux: UDP 21554
sudo ss -ulnp 'sport = :21554'
Linux / macOS: which process owns the port
sudo lsof -nP -i :21554
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':21554 '
Windows (Command Prompt)
netstat -ano | findstr :21554
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 21554 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 21554
From Windows
Test-NetConnection HOST -Port 21554
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 21554

Block port 21554 in the firewall

ufw
sudo ufw deny 21554/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 21554 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 21554 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 21554' -Direction Inbound -Protocol TCP -LocalPort 21554 -Action Block
ufw
sudo ufw deny 21554/udp
iptables
sudo iptables -A INPUT -p udp --dport 21554 -j DROP
nftables
sudo nft add rule inet filter input udp dport 21554 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 21554' -Direction Inbound -Protocol UDP -LocalPort 21554 -Action Block

Related ports

21337xahaud21553rdm-tfs21590vofr-gateway21800tvpm

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