Port 18881 (infotos)

IANA assigns port 18881 to infotos: Infotos.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

infotos TCP Infotos Marcel Dube -

infotos UDP Infotos Marcel Dube -

Registry dates for this port: registered 2004-11.

Linux: is anything listening on TCP 18881?

sudo ss -tlnp 'sport = :18881'

Linux: UDP 18881

sudo ss -ulnp 'sport = :18881'

Linux / macOS: which process owns the port

sudo lsof -nP -i :18881

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':18881 '

Windows (Command Prompt)

netstat -ano | findstr :18881

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 18881 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 18881

From Windows

Test-NetConnection HOST -Port 18881

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 18881

ufw

sudo ufw deny 18881/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 18881 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 18881 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 18881' -Direction Inbound -Protocol TCP -LocalPort 18881 -Action Block

ufw

sudo ufw deny 18881/udp

iptables

sudo iptables -A INPUT -p udp --dport 18881 -j DROP

nftables

sudo nft add rule inet filter input udp dport 18881 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 18881' -Direction Inbound -Protocol UDP -LocalPort 18881 -Action Block

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