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Port 1818 (etftp)

IANA assigns port 1818 to etftp: Enhanced Trivial File Transfer Protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
etftp TCP Enhanced Trivial File Transfer Protocol William Polites -
etftp UDP Enhanced Trivial File Transfer Protocol William Polites -

Check what is listening on port 1818

Linux: is anything listening on TCP 1818?
sudo ss -tlnp 'sport = :1818'
Linux: UDP 1818
sudo ss -ulnp 'sport = :1818'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1818
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1818 '
Windows (Command Prompt)
netstat -ano | findstr :1818
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1818 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1818
From Windows
Test-NetConnection HOST -Port 1818
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1818

Block port 1818 in the firewall

ufw
sudo ufw deny 1818/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1818 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1818 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1818' -Direction Inbound -Protocol TCP -LocalPort 1818 -Action Block
ufw
sudo ufw deny 1818/udp
iptables
sudo iptables -A INPUT -p udp --dport 1818 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1818 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1818' -Direction Inbound -Protocol UDP -LocalPort 1818 -Action Block

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