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Port 1791 (ea1)

IANA assigns port 1791 to ea1: EA1.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
ea1 TCP EA1 Kirk MacLean -
ea1 UDP EA1 Kirk MacLean -

Check what is listening on port 1791

Linux: is anything listening on TCP 1791?
sudo ss -tlnp 'sport = :1791'
Linux: UDP 1791
sudo ss -ulnp 'sport = :1791'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1791
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1791 '
Windows (Command Prompt)
netstat -ano | findstr :1791
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1791 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1791
From Windows
Test-NetConnection HOST -Port 1791
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1791

Block port 1791 in the firewall

ufw
sudo ufw deny 1791/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1791 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1791 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1791' -Direction Inbound -Protocol TCP -LocalPort 1791 -Action Block
ufw
sudo ufw deny 1791/udp
iptables
sudo iptables -A INPUT -p udp --dport 1791 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1791 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1791' -Direction Inbound -Protocol UDP -LocalPort 1791 -Action Block

Related ports

1789hello1790nmsp1792ibm-dt-21793rsc-robot

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