Port 6244 (jeol-nsdtp-4, jeol-nsddp-4)

IANA assigns port 6244 to jeol-nsdtp-4, jeol-nsddp-4: JEOL Network Services Data Transport Protocol 4.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

jeol-nsdtp-4 TCP JEOL Network Services Data Transport Protocol 4 Kevin Wellwood -

jeol-nsddp-4 UDP JEOL Network Services Dynamic Discovery Protocol 4 Kevin Wellwood -

Registry dates for this port: registered 2008-04-17.

Linux: is anything listening on TCP 6244?

sudo ss -tlnp 'sport = :6244'

Linux: UDP 6244

sudo ss -ulnp 'sport = :6244'

Linux / macOS: which process owns the port

sudo lsof -nP -i :6244

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':6244 '

Windows (Command Prompt)

netstat -ano | findstr :6244

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6244 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 6244

From Windows

Test-NetConnection HOST -Port 6244

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

nc -vzu -w 5 HOST 6244

ufw

sudo ufw deny 6244/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 6244 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 6244 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 6244' -Direction Inbound -Protocol TCP -LocalPort 6244 -Action Block

ufw

sudo ufw deny 6244/udp

iptables

sudo iptables -A INPUT -p udp --dport 6244 -j DROP

nftables

sudo nft add rule inet filter input udp dport 6244 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 6244' -Direction Inbound -Protocol UDP -LocalPort 6244 -Action Block

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