Port 42999 (curiosity)

IANA assigns port 42999 to curiosity: API endpoint for search application.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

curiosity TCP API endpoint for search application Curiosity GmbH -

Registry dates for this port: registered 2022-12-09.

Linux: is anything listening on TCP 42999?

sudo ss -tlnp 'sport = :42999'

Linux / macOS: which process owns the port

sudo lsof -nP -i :42999

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':42999 '

Windows (Command Prompt)

netstat -ano | findstr :42999

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 42999 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 42999

From Windows

Test-NetConnection HOST -Port 42999

ufw

sudo ufw deny 42999/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 42999 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 42999 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 42999' -Direction Inbound -Protocol TCP -LocalPort 42999 -Action Block

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