HTTPfy

Port 393 (meta5)

IANA assigns port 393 to meta5: Meta5.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
meta5 TCP Meta5 Jim Kanzler -
meta5 UDP Meta5 Jim Kanzler -

Check what is listening on port 393

Linux: is anything listening on TCP 393?
sudo ss -tlnp 'sport = :393'
Linux: UDP 393
sudo ss -ulnp 'sport = :393'
Linux / macOS: which process owns the port
sudo lsof -nP -i :393
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':393 '
Windows (Command Prompt)
netstat -ano | findstr :393
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 393 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 393
From Windows
Test-NetConnection HOST -Port 393
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 393

Block port 393 in the firewall

ufw
sudo ufw deny 393/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 393 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 393 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 393' -Direction Inbound -Protocol TCP -LocalPort 393 -Action Block
ufw
sudo ufw deny 393/udp
iptables
sudo iptables -A INPUT -p udp --dport 393 -j DROP
nftables
sudo nft add rule inet filter input udp dport 393 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 393' -Direction Inbound -Protocol UDP -LocalPort 393 -Action Block

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391synotics-relay392synotics-broker394embl-ndt395netcp

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