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Port 1581 (mil-2045-47001)

IANA assigns port 1581 to mil-2045-47001: MIL-2045-47001.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
mil-2045-47001 TCP MIL-2045-47001 Eric Whitehill -
mil-2045-47001 UDP MIL-2045-47001 Eric Whitehill -

Check what is listening on port 1581

Linux: is anything listening on TCP 1581?
sudo ss -tlnp 'sport = :1581'
Linux: UDP 1581
sudo ss -ulnp 'sport = :1581'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1581
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1581 '
Windows (Command Prompt)
netstat -ano | findstr :1581
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1581 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1581
From Windows
Test-NetConnection HOST -Port 1581
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1581

Block port 1581 in the firewall

ufw
sudo ufw deny 1581/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1581 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1581 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1581' -Direction Inbound -Protocol TCP -LocalPort 1581 -Action Block
ufw
sudo ufw deny 1581/udp
iptables
sudo iptables -A INPUT -p udp --dport 1581 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1581 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1581' -Direction Inbound -Protocol UDP -LocalPort 1581 -Action Block

Related ports

1579ioc-sea-lm1580tn-tl-r1, tn-tl-r21582msims1583simbaexpress

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