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Port 5021 (zenginkyo-2)

IANA assigns port 5021 to zenginkyo-2.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
zenginkyo-2 TCP zenginkyo-2 Masashi Suzaki -
zenginkyo-2 UDP zenginkyo-2 Masashi Suzaki -

Check what is listening on port 5021

Linux: is anything listening on TCP 5021?
sudo ss -tlnp 'sport = :5021'
Linux: UDP 5021
sudo ss -ulnp 'sport = :5021'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5021
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5021 '
Windows (Command Prompt)
netstat -ano | findstr :5021
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5021 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5021
From Windows
Test-NetConnection HOST -Port 5021
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5021

Block port 5021 in the firewall

ufw
sudo ufw deny 5021/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5021 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5021 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5021' -Direction Inbound -Protocol TCP -LocalPort 5021 -Action Block
ufw
sudo ufw deny 5021/udp
iptables
sudo iptables -A INPUT -p udp --dport 5021 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5021 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5021' -Direction Inbound -Protocol UDP -LocalPort 5021 -Action Block

Related ports

5015fmwp5020zenginkyo-15022mice5023htuilsrv

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