IANA assigns port 1622 to ontime.
sudo ss -tlnp 'sport = :1622'sudo ss -ulnp 'sport = :1622'sudo lsof -nP -i :1622sudo netstat -tlnp | grep ':1622 'netstat -ano | findstr :1622Get-NetTCPConnection -LocalPort 1622 -State Listen | Select LocalAddress,OwningProcessnc -vz -w 5 HOST 1622Test-NetConnection HOST -Port 1622nc -vzu -w 5 HOST 1622sudo ufw deny 1622/tcpsudo iptables -A INPUT -p tcp --dport 1622 -j DROPsudo nft add rule inet filter input tcp dport 1622 dropNew-NetFirewallRule -DisplayName 'Block TCP 1622' -Direction Inbound -Protocol TCP -LocalPort 1622 -Action Blocksudo ufw deny 1622/udpsudo iptables -A INPUT -p udp --dport 1622 -j DROPsudo nft add rule inet filter input udp dport 1622 dropNew-NetFirewallRule -DisplayName 'Block UDP 1622' -Direction Inbound -Protocol UDP -LocalPort 1622 -Action BlockAll port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.