HTTPfy

Port 3221 (xnm-clear-text)

IANA assigns port 3221 to xnm-clear-text: XML NM over TCP.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
xnm-clear-text TCP XML NM over TCP Mark Trostler -
xnm-clear-text UDP XML NM over TCP Mark Trostler -

Check what is listening on port 3221

Linux: is anything listening on TCP 3221?
sudo ss -tlnp 'sport = :3221'
Linux: UDP 3221
sudo ss -ulnp 'sport = :3221'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3221
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3221 '
Windows (Command Prompt)
netstat -ano | findstr :3221
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3221 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3221
From Windows
Test-NetConnection HOST -Port 3221
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3221

Block port 3221 in the firewall

ufw
sudo ufw deny 3221/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3221 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3221 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3221' -Direction Inbound -Protocol TCP -LocalPort 3221 -Action Block
ufw
sudo ufw deny 3221/udp
iptables
sudo iptables -A INPUT -p udp --dport 3221 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3221 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3221' -Direction Inbound -Protocol UDP -LocalPort 3221 -Action Block

Related ports

3219wms-messenger3220xnm-ssl3222glbp3223digivote

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